A U.S. marshal gestures to a crowd of journalists and people who were evacuated from the John Joseph Moakley United States Courthouse back during a bomb threat in Boston, Massachusetts April 17, 2013. Security officials reopened Boston's federal courthouse building to employees on Wednesday afternoon after an hour-long evacuation tied to a security scare. REUTERS/Jessica Rinaldi (UNITED STATES - Tags: CRIME LAW CIVIL UNREST) 

La Palma Police and a US Marshall maintain security after serving a search warrant at the home of Christopher Dorner's mother in La Palma, California February 8, 2013. Authorities continued their manhunt for the fired policeman Christopher Dorner who is suspected of gunning down five people, killing three and declaring an all-out war on police officers and their families in a rambling internet manifesto. REUTERS/PATRICK FALLON (UNITED STATES - Tags: CRIME LAW) 

La Palma Police and a US Marshall maintain security after serving a search warrant at the home of Christopher Dorner's mother in La Palma, California February 8, 2013. Authorities continued their manhunt for the fired policeman Christopher Dorner who is suspected of gunning down five people, killing three and declaring an all-out war on police officers and their families in a rambling internet manifesto. REUTERS/PATRICK FALLON (UNITED STATES - Tags: CRIME LAW) 

Neighbors walk their dog past US Marshals and La Palma Police providing security while detectives search the home of Christopher Dorner's mother after serving a search warrant in La Palma, California February 8, 2013. Authorities continued their manhunt for the fired policeman Christopher Dorner who is suspected of gunning down five people, killing three and declaring an all-out war on police officers and their families in a rambling internet manifesto. REUTERS/PATRICK FALLON (UNITED STATES - Tags: CRIME LAW) 

La Palma Police and US Marshals provide security outside the home of Christopher Dorner's mother while investigators work serving a search warrant in La Palma, California February 8, 2013. Authorities continued their manhunt for the fired policeman Christopher Dorner who is suspected of gunning down five people, killing three and declaring an all-out war on police officers and their families in a rambling internet manifesto. REUTERS/PATRICK FALLON (UNITED STATES - Tags: CRIME LAW) 

A man walks past a graffiti of Egypt's former president Hosni Mubarak, former Field Marshal Mohamed Hussein Tantawi and Muslim Brotherhood leader Mohamed Badie along Mohamed Mahmoud street near Tahrir Square in Cairo, September 26, 2012. The graffiti on the walls of Mohamed Mahmoud Street had existed since November 2011, where some of the fiercest fighting between protesters and security forces took place. The Arabic words read, "The one who gave the commands, still lives , "It is a shaky regime that fears a pen and a brush, an oppressive regime which suppresses those who oppose". REUTERS/Amr Abdallah Dalsh (EGYPT - Tags: POLITICS CIVIL UNREST) 

A policeman stands guard in front of a graffiti with Egypt's former president Hosni Mubarak, former Field Marshal Mohamed Hussein Tantawi and Muslim Brotherhood leader Mohamed Badie along Mohamed Mahmoud street near Tahrir Square in Cairo, September 26, 2012. The graffiti on the walls of Mohamed Mahmoud Street had existed since November 2011, where some of the fiercest fighting between protesters and security forces took place. The Arabic words read, "The one who gave the commands, still lives". REUTERS/Amr Abdallah Dalsh (EGYPT - Tags: POLITICS CIVIL UNREST SOCIETY) 

Rory McIlroy (L) looks on as a marshal helps secure his golf ball lodged in a tree during the third round of the PGA Championship golf tournament at The Ocean Course on Kiawah Island, South Carolina, August 11, 2012. REUTERS/Mathieu Belanger (UNITED STATES - Tags: SPORT GOLF)

Members of "Field Marshal Hussein Tantawi," a group consisting of official and police guards, try to ride a military police vehicle after a funeral for soldiers who were killed during an attack at a checkpoint along the Sinai border with Israel by unknown gunmen, at the tomb of the late President Anwar al-Sadat and the Unknown Soldier monument in Cairo August 7, 2012. Egypt began work to seal off smuggling tunnels into the Gaza Strip on Tuesday, a security source said, two days after gunmen shot dead 16 Egyptian border guards in an attack blamed partly on Palestinian jihadi militants. REUTERS/Amr Abdallah Dalsh (EGYPT - Tags: CIVIL UNREST MILITARY OBITUARY) 

Members of "Field Marshal Hussein Tantawi," a group consisting of official and police guards, try to ride a military police vehicle after the funeral for soldiers who were killed during an attack at a checkpoint along the Sinai border with Israel by unknown gunmen, at the tomb of the late President Anwar al-Sadat and the Unknown Soldier monument in Cairo August 7, 2012. Egypt began work to seal off smuggling tunnels into the Gaza Strip on Tuesday, a security source said, two days after gunmen shot dead 16 Egyptian border guards in an attack blamed partly on Palestinian jihadi militants. REUTERS/Amr Abdallah Dalsh (EGYPT - Tags: CIVIL UNREST MILITARY POLITICS OBITUARY) 

A combination photograph shows members of "Field Marshal Hussein Tantawi," a group consisting of official and police guards, trying to ride a military police vehicle after a funeral for soldiers who were killed during an attack at a checkpoint along the Sinai border with Israel by unknown gunmen, at the tomb of the late President Anwar al-Sadat and the Unknown Soldier monument in Cairo August 7, 2012. Egypt began work to seal off smuggling tunnels into the Gaza Strip on Tuesday, a security source said, two days after gunmen shot dead 16 Egyptian border guards in an attack blamed partly on Palestinian jihadi militants. REUTERS/Amr Abdallah Dalsh (EGYPT - Tags: CIVIL UNREST MILITARY POLITICS OBITUARY TPX IMAGES OF THE DAY) 

Head of Egypt's military Field Marshal Hussein Tantawi attends the funeral of soldiers, who were killed during an attack at a checkpoint along the Sinai border with Israel by unknown gunmen, at the tomb of the late President Anwar al-Sadat and the Unknown Soldier monument in Cairo August 7, 2012. Egypt began work to seal off smuggling tunnels into the Gaza Strip on Tuesday, a security source said, two days after gunmen shot dead 16 Egyptian border guards in an attack blamed partly on Palestinian jihadi militants. REUTERS/Amr Abdallah Dalsh (EGYPT - Tags: POLITICS CIVIL UNREST MILITARY OBITUARY) 

Field Marshal Hussein Tantawi (7th R), head of Egypt's military, Armed Forces Chief of Staff Sami Anan (8th R), Kamal Ganzouri (6th R), adviser to the Egyptian president, and Amr Moussa (5th R), former Arab League chief and former presidential candidate, walk with other ministers during the funeral of soldiers killed during an attack at a checkpoint along the Sinai border with Israel by unknown gunmen, at the tomb of the late President Anwar al-Sadat and the Unknown Soldier monument in Cairo August 7, 2012. Egypt began work to seal off smuggling tunnels into the Gaza Strip on Tuesday, a security source said, two days after gunmen shot dead 16 Egyptian border guards in an attack blamed partly on Palestinian jihadi militants. REUTERS/Amr Abdallah Dalsh (EGYPT - Tags: CIVIL UNREST MILITARY POLITICS OBITUARY) 

Field Marshal Hussein Tantawi (C), head of Egypt's military, Armed Forces Chief of Staff Sami Anan (3rd L), Kamal Ganzouri (2nd R), adviser to the Egyptian president, and Amr Moussa (R), former Arab League chief and former presidential candidate, walk during the funeral of soldiers killed during an attack at a checkpoint along the Sinai border with Israel by unknown gunmen, at the tomb of the late President Anwar al-Sadat and the Unknown Soldier monument in Cairo August 7, 2012. Egypt began work to seal off smuggling tunnels into the Gaza Strip on Tuesday, a security source said, two days after gunmen shot dead 16 Egyptian border guards in an attack blamed partly on Palestinian jihadi militants. REUTERS/Amr Abdallah Dalsh (EGYPT - Tags: POLITICS CIVIL UNREST MILITARY OBITUARY) 

The head of Egypt's military, Field Marshal Hussein Tantawi (C), and Armed Forces Chief of Staff Sami Anan (R) attend the funeral of soldiers, who were killed during an attack at a checkpoint along the Sinai border with Israel by unknown gunmen, at the tomb of the late President Anwar al-Sadat and the Unknown Soldier monument in Cairo August 7, 2012. Egypt began work to seal off smuggling tunnels into the Gaza Strip on Tuesday, a security source said, two days after gunmen shot dead 16 Egyptian border guards in an attack blamed partly on Palestinian jihadi militants. REUTERS/Amr Abdallah Dalsh (EGYPT - Tags: CIVIL UNREST MILITARY POLITICS OBITUARY) 

Members of "Field Marshal Hussein Tantawi," a group consisting of official and police guards, try to ride a military police vehicle after the funeral for soldiers, who were killed during an attack at a checkpoint along the Sinai border with Israel by unknown gunmen, at the tomb of the late President Anwar al-Sadat and the Unknown Soldier monument in Cairo August 7, 2012. Egypt began work to seal off smuggling tunnels into the Gaza Strip on Tuesday, a security source said, two days after gunmen shot dead 16 Egyptian border guards in an attack blamed partly on Palestinian jihadi militants. REUTERS/Amr Abdallah Dalsh (EGYPT - Tags: POLITICS CIVIL UNREST MILITARY OBITUARY) 

Members of "Field Marshal Hussein Tantawi," a group consisting of official and police guards, try to ride a military police vehicle after the funeral for soldiers, who were killed during an attack at a checkpoint along the Sinai border with Israel by unknown gunmen, at the tomb of the late President Anwar al-Sadat and the Unknown Soldier monument in Cairo August 7, 2012. Egypt began work to seal off smuggling tunnels into the Gaza Strip on Tuesday, a security source said, two days after gunmen shot dead 16 Egyptian border guards in an attack blamed partly on Palestinian jihadi militants. REUTERS/Amr Abdallah Dalsh (EGYPT - Tags: CIVIL UNREST MILITARY POLITICS OBITUARY) 

Members of "Field Marshal Hussein Tantawi," a group consisting of official and police guards, try to ride a military police vehicle after a funeral for soldiers who were killed during an attack at a checkpoint along the Sinai border with Israel by unknown gunmen, at the tomb of the late President Anwar al-Sadat and the Unknown Soldier monument in Cairo August 7, 2012. Egypt began work to seal off smuggling tunnels into the Gaza Strip on Tuesday, a security source said, two days after gunmen shot dead 16 Egyptian border guards in an attack blamed partly on Palestinian jihadi militants. REUTERS/Amr Abdallah Dalsh (EGYPT - Tags: CIVIL UNREST MILITARY OBITUARY) 

Field Marshal Hussein Tantawi attends a meeting with Egypt's president Mohamed Mursi and U.S. Secretary of Defense Leon Panetta at the presidential palace in Cairo July 31, 2012. Panetta arrived in Cairo on Tuesday to meet Egypt's new Islamist president and its top general, seeking to balance security concerns with efforts to promote the country's still wobbly transition to democracy. REUTERS/Amr Abdallah Dalsh (EGYPT - Tags: POLITICS) 

Field Marshal Hussein Tantawi attends a meeting with Egypt's president Mohamed Mursi and U.S. Secretary of Defense Leon Panetta at the presidential palace in Cairo July 31, 2012. Panetta arrived in Cairo on Tuesday to meet Egypt's new Islamist president and its top general, seeking to balance security concerns with efforts to promote the country's still wobbly transition to democracy. REUTERS/Amr Abdallah Dalsh (EGYPT - Tags: POLITICS) 

Field Marshal Hussein Tantawi attends a meeting with Egypt's president Mohamed Mursi and U.S. Secretary of Defense Leon Panetta (not pictured) at the presidential palace in Cairo July 31, 2012. Panetta arrived in Cairo on Tuesday to meet Egypt's new Islamist president and its top general, seeking to balance security concerns with efforts to promote the country's still wobbly transition to democracy. REUTERS/Amr Abdallah Dalsh (EGYPT - Tags: POLITICS) 

Field Marshal Hussein Tantawi (L) and U.S. Secretary of Defense Leon Panetta attend a during meeting with Egypt's president Mohamed Mursi (not pictured) at the presidential palace in Cairo July 31, 2012. Panetta arrived in Cairo on Tuesday to meet Egypt's new Islamist president and its top general, seeking to balance security concerns with efforts to promote the country's still wobbly transition to democracy. REUTERS/Amr Abdallah Dalsh (EGYPT - Tags: POLITICS) 

Field Marshal Hussein Tantawi attends a meeting with Egypt's president Mohamed Mursi and U.S. Secretary of Defense Leon Panetta at the presidential palace in Cairo July 31, 2012. Panetta arrived in Cairo on Tuesday to meet Egypt's new Islamist president and its top general, seeking to balance security concerns with efforts to promote the country's still wobbly transition to democracy. REUTERS/Amr Abdallah Dalsh (EGYPT - Tags: POLITICS MILITARY) 

Egypt's president Mohamed Mursi (R) meets with U.S. Secretary of Defense Leon Panetta and Field Marshal Hussein Tantawi (L) at the presidential palace in Cairo July 31, 2012. Panetta arrived in Cairo on Tuesday to meet Egypt's new Islamist president and its top general, seeking to balance security concerns with efforts to promote the country's still wobbly transition to democracy. REUTERS/Amr Abdallah Dalsh (EGYPT - Tags: POLITICS MILITARY) 

(L-R) Associate Regional Director and Enforcement Director David Peavler, Regional Director David Woodcock and Associate Regional Director for Examinations Marshall Gandy talk with one another in Woodcock's office at the Fort Worth Regional Office of the Securities and Exchange Commission (SEC) in Fort Worth, Texas June 28, 2012. Picture taken June 28, 2012. To match Feature SEC-FORTWORTH/ REUTERS/Mike Stone (UNITED STATES - Tags: BUSINESS POLITICS) 

A book titled 'Ponzimonium' is seen in the foreground as Regional Director David Woodcock (top R) talks with Associate Regional Director for Examinations Marshall Gandy (not pictured) and Associate Regional Director and Enforcement Director David Peavler (bottom R) in Woodcock's office at the Fort Worth Regional Office of the Securities and Exchange Commission (SEC) in Fort Worth, Texas June 28, 2012. Picture taken June 28, 2012. To match Feature SEC-FORTWORTH/ REUTERS/Mike Stone (UNITED STATES - Tags: BUSINESS POLITICS) 

Staff Accountant Joshua N. Newburn (L) and Associate Regional Director for Examinations Marshall Gandy talk in Gandy's office at the Fort Worth Regional Office of the Securities and Exchange Commission (SEC) in Fort Worth, Texas June 28, 2012. Picture taken June 28, 2012. To match Feature SEC-FORTWORTH/ REUTERS/Mike Stone (UNITED STATES - Tags: BUSINESS POLITICS) 

(L-R) Associate Regional Director for Examinations Marshall Gandy, Associate Regional Director and Enforcement Director David Peavler and Regional Director David Woodcock talk with each other in Woodcock's office at the Fort Worth Regional Office of the Securities and Exchange Commission (SEC) in Fort Worth, Texas June 28, 2012. Picture taken June 28, 2012. To match Feature SEC-FORTWORTH/ REUTERS/Mike Stone (UNITED STATES - Tags: BUSINESS POLITICS) 

A book titled 'Ponzimonium' is seen in the foreground as Regional Director David Woodcock (L) talks with Associate Regional Director for Examinations Marshall Gandy (R and Associate Regional Director and Enforcement Director David Peavler in Woodcock's office at the Fort Worth Regional Office of the Security Exchange Commission (SEC) in Fort Worth, Texas June 28, 2012. Picture taken June 28, 2012. To match Feature SEC-FORTWORTH/ REUTERS/Mike Stone (UNITED STATES - Tags: BUSINESS POLITICS) 

(L-R) Associate Regional Director and Enforcement Director David Peavler, Regional Director David Woodcock and Associate Regional Director for Examinations Marshall Gandy pose at the Fort Worth Regional Office of the Security Exchange Commission in Fort Worth, Texas June 28, 2012. Picture taken June 28, 2012. To match Feature SEC-FORTWORTH/ REUTERS/Mike Stone (UNITED STATES - Tags: BUSINESS POLITICS) 

U.S. Marshal Michael Dyke, who still searches for three convicts who escaped from Alcatraz Island's federal prison fifty years ago, speaks on a panel marking the escape's anniversary on Monday, June 11, 2012, in the San Francisco Bay. Behind Dyke are family members of the Anglin brothers who, along with fellow inmate Frank Morris, disappeared from the maximum security prison on June 11, 1962. REUTERS/Noah Berger (UNITED STATES - Tags: CRIME LAW) 

People walk in front of a wall sprayed with graffiti, depicting the ruling military council controlling the presidential elections as a puppet show and a mural depicting presidential candidate and former prime minister Ahmed Shafiq (L), former presidential candidate Amr Moussa and Field Marshal Mohamed Hussein Tantawi near Tahrir Square during a demonstration in Cairo June 5, 2012. Activists urged Egyptians to turn out for a big protest on Tuesday to reclaim a revolt they say has been hijacked after Hosni Mubarak was jailed for life but top security officials freed in a trial seen as a sign his old guard remain in charge. REUTERS/Amr Abdallah Dalsh (EGYPT - Tags: POLITICS CIVIL UNREST) 

A protester holds an Egyptian flag in front of a mural depicting presidential candidate Ahmed Shafiq (L) and a combination of the faces of former president Hosni Mubarak and Field Marshal Mohamed Hussein Tantawi at Tahrir Square in Cairo May 25, 2012. The prospect of Shafiq succeeding Mubarak as president of Egypt is a nightmare for revolutionaries and Islamists, but a security blanket for those wary of change. REUTERS/Suhaib Salem (EGYPT - Tags: POLITICS CIVIL UNREST) 

A mural depicting presidential candidate Ahmed Shafiq (L) and a combination of the faces of former president Hosni Mubarak and Field Marshal Mohamed Hussein Tantawi are seen during a protest against Shafiq at Tahrir Square in Cairo May 25, 2012. The prospect of Shafiq succeeding Mubarak as president of Egypt is a nightmare for revolutionaries and Islamists, but a security blanket for those wary of change. REUTERS/Suhaib Salem (EGYPT - Tags: POLITICS CIVIL UNREST) 

A security personnel walks in front of the Marshall Fields building ahead of the NATO meeting in Chicago, May 19, 2012. REUTERS/Darren Hauck (UNITED STATES - Tags: POLITICS) 

Protesters shout as security forces with armoured vehicles push protesters away from Abbasiya square near Egypt's Defence Ministry May 4, 2012. Protesters threw rocks at troops guarding Egypt's defence ministry on Friday as thousands marched in Cairo to denounce violence against demonstrators and the exclusion of candidates from the presidential election. The crowd hurled projectiles and insults at the soldiers sent to defend the ministry after 11 people were killed in clashes there on Wednesday, and called for the overthrow of the head of the ruling army council, Field Marshal Hussein Tantawi. REUTERS /Asmaa Waguih (EGYPT - Tags: POLITICS CIVIL UNREST MILITARY) 

Security forces throw stones back at protesters near Egypt's Defence Ministry May 4, 2012. Protesters threw rocks at troops guarding Egypt's defence ministry on Friday as thousands marched in Cairo to denounce violence against demonstrators and the exclusion of candidates from the presidential election. The crowd hurled projectiles and insults at the soldiers sent to defend the ministry after 11 people were killed in clashes there on Wednesday, and called for the overthrow of the head of the ruling army council, Field Marshal Hussein Tantawi. REUTERS /Asmaa Waguih (EGYPT - Tags: POLITICS CIVIL UNREST MILITARY) 

Protesters help fellow demonstrators suffering from the effects of the tear gas thrown by security forces near Egypt's Defence Ministry May 4, 2012. Protesters threw rocks at troops guarding Egypt's defence ministry on Friday as thousands marched in Cairo to denounce violence against demonstrators and the exclusion of candidates from the presidential election. The crowd hurled projectiles and insults at the soldiers sent to defend the ministry after 11 people were killed in clashes there on Wednesday, and called for the overthrow of the head of the ruling army council, Field Marshal Hussein Tantawi. REUTERS /Asmaa Waguih (EGYPT - Tags: POLITICS CIVIL UNREST) 

A protester runs from tear gas thrown by security forces near Egypt's Defence Ministry May 4, 2012. Protesters threw rocks at troops guarding Egypt's defence ministry on Friday as thousands marched in Cairo to denounce violence against demonstrators and the exclusion of candidates from the presidential election. The crowd hurled projectiles and insults at the soldiers sent to defend the ministry after 11 people were killed in clashes there on Wednesday, and called for the overthrow of the head of the ruling army council, Field Marshal Hussein Tantawi. REUTERS /Asmaa Waguih (EGYPT - Tags: POLITICS CIVIL UNREST) 

A protester shouts while others run as security forces with armoured vehicles push them away from Abbasiya square near Egypt's Defence Ministry May 4, 2012. Protesters threw rocks at troops guarding Egypt's defence ministry on Friday as thousands marched in Cairo to denounce violence against demonstrators and the exclusion of candidates from the presidential election. The crowd hurled projectiles and insults at the soldiers sent to defend the ministry after 11 people were killed in clashes there on Wednesday, and called for the overthrow of the head of the ruling army council, Field Marshal Hussein Tantawi. REUTERS /Asmaa Waguih (EGYPT - Tags: POLITICS CIVIL UNREST MILITARY) 

A protester throws a tear gas canister back at security forces near Egypt's Defence Ministry May 4, 2012. Protesters threw rocks at troops guarding Egypt's defence ministry on Friday as thousands marched in Cairo to denounce violence against demonstrators and the exclusion of candidates from the presidential election. The crowd hurled projectiles and insults at the soldiers sent to defend the ministry after 11 people were killed in clashes there on Wednesday, and called for the overthrow of the head of the ruling army council, Field Marshal Hussein Tantawi. REUTERS /Asmaa Waguih (EGYPT - Tags: POLITICS CIVIL UNREST) 

Protesters help a fellow demonstrator affected by the tear gas thrown by security forces near Egypt's Defence Ministry May 4, 2012. Protesters threw rocks at troops guarding Egypt's defence ministry on Friday as thousands marched in Cairo to denounce violence against demonstrators and the exclusion of candidates from the presidential election. The crowd hurled projectiles and insults at the soldiers sent to defend the ministry after 11 people were killed in clashes there on Wednesday, and called for the overthrow of the head of the ruling army council, Field Marshal Hussein Tantawi. REUTERS /Asmaa Waguih (EGYPT - Tags: POLITICS CIVIL UNREST) 

Protesters help a fellow demonstrator affected by the tear gas thrown by security forces near Egypt's Defence Ministry May 4, 2012. Protesters threw rocks at troops guarding Egypt's defence ministry on Friday as thousands marched in Cairo to denounce violence against demonstrators and the exclusion of candidates from the presidential election. The crowd hurled projectiles and insults at the soldiers sent to defend the ministry after 11 people were killed in clashes there on Wednesday, and called for the overthrow of the head of the ruling army council, Field Marshal Hussein Tantawi. REUTERS /Asmaa Waguih (EGYPT - Tags: POLITICS CIVIL UNREST) 

A protester catches a tear gas canister thrown by security forces near Egypt's Defence Ministry May 4, 2012. Protesters threw rocks at troops guarding Egypt's defence ministry on Friday as thousands marched in Cairo to denounce violence against demonstrators and the exclusion of candidates from the presidential election. The crowd hurled projectiles and insults at the soldiers sent to defend the ministry after 11 people were killed in clashes there on Wednesday, and called for the overthrow of the head of the ruling army council, Field Marshal Hussein Tantawi. REUTERS /Asmaa Waguih (EGYPT - Tags: POLITICS CIVIL UNREST TPX IMAGES OF THE DAY) 

A protester catches a tear gas canister thrown by security forces near Egypt's Defence Ministry May 4, 2012. Protesters threw rocks at troops guarding Egypt's defence ministry on Friday as thousands marched in Cairo to denounce violence against demonstrators and the exclusion of candidates from the presidential election. The crowd hurled projectiles and insults at the soldiers sent to defend the ministry after 11 people were killed in clashes there on Wednesday, and called for the overthrow of the head of the ruling army council, Field Marshal Hussein Tantawi. REUTERS /Asmaa Waguih (EGYPT - Tags: POLITICS CIVIL UNREST) 

Security forces throw stones back at protesters near Egypt's Defence Ministry May 4, 2012. Protesters threw rocks at troops guarding Egypt's defence ministry on Friday as thousands marched in Cairo to denounce violence against demonstrators and the exclusion of candidates from the presidential election. The crowd hurled projectiles and insults at the soldiers sent to defend the ministry after 11 people were killed in clashes there on Wednesday, and called for the overthrow of the head of the ruling army council, Field Marshal Hussein Tantawi. REUTERS /Asmaa Waguih (EGYPT - Tags: CIVIL UNREST MILITARY) 

Security forces throw stones back at protesters near Egypt's Defence Ministry May 4, 2012. Protesters threw rocks at troops guarding Egypt's defence ministry on Friday as thousands marched in Cairo to denounce violence against demonstrators and the exclusion of candidates from the presidential election. The crowd hurled projectiles and insults at the soldiers sent to defend the ministry after 11 people were killed in clashes there on Wednesday, and called for the overthrow of the head of the ruling army council, Field Marshal Hussein Tantawi. REUTERS /Asmaa Waguih (EGYPT - Tags: POLITICS CIVIL UNREST MILITARY) 

A member of security forces jumps before throwing a stone back at protesters near Egypt's Defence Ministry May 4, 2012. Protesters threw rocks at troops guarding Egypt's defence ministry on Friday as thousands marched in Cairo to denounce violence against demonstrators and the exclusion of candidates from the presidential election. The crowd hurled projectiles and insults at the soldiers sent to defend the ministry after 11 people were killed in clashes there on Wednesday, and called for the overthrow of the head of the ruling army council, Field Marshal Hussein Tantawi. REUTERS /Asmaa Waguih (EGYPT - Tags: MILITARY CIVIL UNREST TPX IMAGES OF THE DAY) 

Air Vice Marshal Stuart Atha, the Air Component Commander for Olympics Air Security, poses for photographers at RAF Northolt in west London May 2, 2012. Four Typhoon jets arrived at the base on Wednesday to take part in defence exercises in advance of the London 2012 Olympic Games. REUTERS/Paul Hackett (BRITAIN - Tags: MILITARY SPORT OLYMPICS) 

Air Vice Marshal Stuart Atha, the Air Component Commander for Olympics Air Security, poses for photographers at RAF Northolt in west London May 2, 2012. Four Typhoon jets arrived at the base on Wednesday to take part in defence exercises in advance of the London 2012 Olympic Games. REUTERS/Paul Hackett (BRITAIN - Tags: MILITARY SPORT OLYMPICS) 

Security guards use binoculars to keep watch during the Algeria Cup final soccer match between CR Belcourt and Entente Setif in Algiers, May 1, 2012. REUTERS/Louafi Larbi (ALGERIA - Tags: SPORT SOCCER) 

People walk in front of a wall sprayed with graffiti depicting Field Marshal Hussein Tantawi (L) and martyrs at Mohamed Mahmoud street, which leads to the Interior Ministry, where clashes between protesters and security forces took place during the revolution in downtown Cairo April 1, 2012. REUTERS/Amr Abdallah Dalsh (EGYPT - Tags: CIVIL UNREST MILITARY POLITICS) 

An Egyptian man walks in front of a wall sprayed with graffiti depicting the faces of Field Marshal Hussein Tantawi (C) and his assistants at Mohamed Mahmoud street, which leads to the Interior Ministry, where clashes between protesters and security force took place during the revolution in downtown Cairo April 1, 2012. REUTERS/Amr Abdallah Dalsh (EGYPT - Tags: CIVIL UNREST MILITARY POLITICS) 

An Egyptian man walks in front of a wall sprayed with graffiti depicting the faces of former President Hosni Mubarak (R) and Field Marshal Hussein Tantawi at Mohamed Mahmoud street, which leads to the Interior Ministry, where clashes between protesters and security force took place during the revolution in downtown Cairo April 1, 2012. REUTERS/Amr Abdallah Dalsh (EGYPT - Tags: CIVIL UNREST MILITARY POLITICS SOCIETY) 

A marshal looks on during second round play in the WGC-Cadillac Championship PGA golf tournament at the Doral Golf Resort in Doral, Florida, March 9, 2012. REUTERS/Andrew Innerarity (UNITED STATES - Tags: SPORT GOLF) 

Amine El Khalifi is pictured in this police photograph released to Reuters February 21, 2012. Authorities arrested El Khalifi on February 17, 2012 near the U.S. Capitol as part of a terrorism investigation, saying he sought to use explosives, according to the U.S. Justice Department and Capitol Police. The 29-year-old Moroccan illegal immigrant who lives in Alexandria, Virginia, was charged with attempting to use a weapon of mass destruction against property owned and used by the United States, intending to detonate a bomb and to shoot people, the department said. REUTERS/U.S. Marshals Service/Handout (UNITED STATES - Tags: CRIME LAW POLITICS CIVIL UNREST) FOR EDITORIAL USE ONLY. NOT FOR SALE FOR MARKETING OR ADVERTISING CAMPAIGNS. THIS IMAGE HAS BEEN SUPPLIED BY A THIRD PARTY. IT IS DISTRIBUTED, EXACTLY AS RECEIVED BY REUTERS, AS A SERVICE TO CLIENTS 

A young protester is seen behind a riot police shield near Tahrir Square in Cairo, December 19, 2011. Egyptian security forces fought opponents of army rule in Cairo for a fourth day on Monday and the United States, worried by the violence, urged the generals to respect human rights. The shield was taken by protesters during Sunday's clashes with security forces. The words on the shield read: "The Field Marshal is Mubarak?s dog". REUTERS/Asmaa Waguih (EGYPT - Tags: POLITICS CIVIL UNREST) 

A boy walks past graffiti that reads "Marshal massacres the street "and "Freedom will be coming" during clashes with security forces in Cairo December 18, 2011. Protesters and troops fought in Cairo on Sunday, the third day of clashes that have killed 10 people and exposed rifts over the army's role as it manages Egypt's promised transition from military to civilian rule REUTERS/Amr Abdallah Dalsh (EGYPT - Tags: CIVIL UNREST POLITICS) 

Protesters chant slogans against head of the ruling military council, Field Marshal Mohamed Hussein Tantawi during clashes in front of the Security Administrative building in Alexandria November 23, 2011. After six days of violence that has killed more than 30 and four days before voting for parliament begins, there was no sign of an end to the confrontation between Egypt's military rulers and liberals keen to complete a revolt that ousted Hosni Mubarak in February by installing an interim civilian administration. REUTERS/Mohamed Abd El-Ghany (EGYPT - Tags: CIVIL UNREST POLITICS) 

Prince Charles of Britain descends the steps of the U.S. Supreme Court with Justice Stephen Breyer, with their security details, after a reception for Marshall scholarship alumni in Washington May 3, 2011. REUTERS/Jonathan Ernst (UNITED STATES - Tags: POLITICS CRIME LAW ROYALS)