Police waits outside the apartment of 29-year-old Sief Allah H., in Cologne, Germany, June 15, 2018, a Tunisian man who was detained on June 13, 2018, suspected of planning an Islamist-motivated attack and the manufacturing of a "biological weapon" using ricin. REUTERS/Thilo Schmuelgen 

Police waits outside the apartment of 29-year-old Sief Allah H., in Cologne, Germany, June 15, 2018, a Tunisian man who was detained on June 13, 2018, suspected of planning an Islamist-motivated attack and the manufacturing of a "biological weapon" using ricin. REUTERS/Thilo Schmuelgen 

An official carries a plastic barrel outside the apartment of 29-year-old Sief Allah H., in Cologne, Germany, June 15, 2018, a Tunisian man who was detained on June 13, 2018, suspected of planning an Islamist-motivated attack and the manufacturing of a "biological weapon" using ricin. REUTERS/Thilo Schmuelgen 

A official carries a plastic barrel outside the apartment of 29-year-old Sief Allah H., in Cologne, Germany, June 15, 2018, a Tunisian man who was detained on June 13, 2018, suspected of planning an Islamist-motivated attack and the manufacturing of a "biological weapon" using ricin. REUTERS/Thilo Schmuelgen 

German police secures the area around the apartment of 29-year-old Sief Allah H., in Cologne, Germany, June 15, 2018, a Tunisian man who was detained on June 13, 2018, suspected of planning an Islamist-motivated attack and the manufacturing of a "biological weapon" using ricin. REUTERS/Thilo Schmuelgen 

Media waits near the apartment of 29-year-old Sief Allah H., in Cologne, Germany, June 15, 2018, a Tunisian man who was detained on June 13, 2018, suspected of planning an Islamist-motivated attack and the manufacturing of a "biological weapon" using ricin. REUTERS/Thilo Schmuelgen 

German police secures the area around the apartment of 29-year-old Sief Allah H., in Cologne, Germany, June 15, 2018, a Tunisian man who was detained on June 13, 2018, suspected of planning an Islamist-motivated attack and the manufacturing of a "biological weapon" using ricin. REUTERS/Thilo Schmuelgen 

German police secures the area around the apartment of 29-year-old Sief Allah H., in Cologne, Germany, June 15, 2018, a Tunisian man who was detained on June 13, 2018, suspected of planning an Islamist-motivated attack and the manufacturing of a "biological weapon" using ricin. REUTERS/Thilo Schmuelgen 

German officials talk in front of the apartment of a 29-year-old Sief Allah H., in Cologne, Germany, June 15, 2018, a Tunisian man who was detained on June 13, 2018, suspected of planning an Islamist-motivated attack and the manufacturing of a "biological weapon" using ricin. REUTERS/Thilo Schmuelgen 

German officials in protective suits leave the apartment of 29-year-old Sief Allah H., in Cologne, Germany, June 15, 2018, a Tunisian man who was detained on June 13, 2018, suspected of planning an Islamist-motivated attack and the manufacturing of a "biological weapon" using ricin. REUTERS/Thilo Schmuelgen 

German police secures the area around the apartment of 29-year-old Sief Allah H., in Cologne, Germany, June 15, 2018, a Tunisian man who was detained on June 13, 2018, suspected of planning an Islamist-motivated attack and the manufacturing of a "biological weapon" using ricin. REUTERS/Thilo Schmuelgen 

A sign listing details of different chemical weapons hangs on a wall at the Research Institute for Protective Technologies, Nuclear, Biological and Chemical Protection (WIS) in Munster October 15, 2013. The state-owned WIS is a reference laboratory for the Organisation for the Prohibition of Chemical Weapons (OPCW). Picture taken October 15, 2013. REUTERS/Fabrizio Bensch (GERMANY - Tags: MILITARY SCIENCE TECHNOLOGY) 

An employee checks his gasmask before decontaminating a military vehicle in the nuclear department at the Research Institute for Protective Technologies, Nuclear, Biological and Chemical Protection (WIS) during a demonstration in Munster October 15, 2013. The state-owned WIS is a reference laboratory for the Organisation for the Prohibition of Chemical Weapons (OPCW). Picture taken October 15, 2013. REUTERS/Fabrizio Bensch (GERMANY - Tags: MILITARY SCIENCE TECHNOLOGY) 

Employees wearing protective clothing decontaminate a military vehicle at the nuclear department at the Research Institute for Protective Technologies, Nuclear, Biological and Chemical Protection (WIS) during a demonstration in Munster October 15, 2013. The state-owned WIS is a reference laboratory for the Organisation for the Prohibition of Chemical Weapons (OPCW). Picture taken October 15, 2013. REUTERS/Fabrizio Bensch (GERMANY - Tags: MILITARY SCIENCE TECHNOLOGY) 

An employee of the Research Institute for Protective Technologies, Nuclear, Biological and Chemical Protection (WIS) uses a detector to check a dummy sample which is contaminated with a substance similar to the chemical weapon Sarin, during a demonstration in Munster October 15, 2013. The state-owned WIS is a reference laboratory for the Organisation for the Prohibition of Chemical Weapons (OPCW). Picture taken October 15, 2013. REUTERS/Fabrizio Bensch (GERMANY - Tags: MILITARY SCIENCE TECHNOLOGY) 

Protective clothing lies on the floor in the nuclear department at the Research Institute for Protective Technologies, Nuclear, Biological and Chemical Protection (WIS) during a demonstration in Munster October 15, 2013. The state-owned WIS is a reference laboratory for the Organisation for the Prohibition of Chemical Weapons (OPCW). Picture taken October 15, 2013. REUTERS/Fabrizio Bensch (GERMANY - Tags: MILITARY SCIENCE TECHNOLOGY) 

Employees of the Research Institute for Protective Technologies, Nuclear, Biological and Chemical Protection (WIS) inspect a dummy sample which is contaminated with a substance similar to the chemical weapon Sarin, during a demonstration in Munster October 15, 2013. The state-owned WIS is a reference laboratory for the Organisation for the Prohibition of Chemical Weapons (OPCW). Picture taken October 15, 2013. REUTERS/Fabrizio Bensch (GERMANY - Tags: MILITARY SCIENCE TECHNOLOGY) 

An employee behind a protective window controls a robot to prepare a dummy substance in the nuclear laboratory at the Research Institute for Protective Technologies, Nuclear, Biological and Chemical Protection (WIS) during a demonstration in Munster October 15, 2013. The state-owned WIS is a reference laboratory for the Organisation for the Prohibition of Chemical Weapons (OPCW). Picture taken October 15, 2013. REUTERS/Fabrizio Bensch (GERMANY - Tags: MILITARY SCIENCE TECHNOLOGY) 

Employees wearing protective clothing decontaminate a military vehicle at the nuclear department at the Research Institute for Protective Technologies, Nuclear, Biological and Chemical Protection (WIS) during a demonstration in Munster October 15, 2013. The state-owned WIS is a reference laboratory for the Organisation for the Prohibition of Chemical Weapons (OPCW). Picture taken October 15, 2013. REUTERS/Fabrizio Bensch (GERMANY - Tags: MILITARY SCIENCE TECHNOLOGY) 

A sign reading 'Experiments with Sarin' hangs on a wall at the Research Institute for Protective Technologies, Nuclear, Biological and Chemical Protection (WIS) in Munster October 15, 2013. The state-owned WIS is a reference laboratory for the Organisation for the Prohibition of Chemical Weapons (OPCW). Picture taken October 15, 2013. REUTERS/Fabrizio Bensch (GERMANY - Tags: MILITARY SCIENCE TECHNOLOGY) 

Employees of the Research Institute for Protective Technologies, Nuclear, Biological and Chemical Protection (WIS) carry a container with a dummy sample which is contaminated with a substance similar to the chemical weapon Sarin, during a demonstration in Munster October 15, 2013. The state-owned WIS is a reference laboratory for the Organisation for the Prohibition of Chemical Weapons (OPCW). Picture taken October 15, 2013. REUTERS/Fabrizio Bensch (GERMANY - Tags: MILITARY SCIENCE TECHNOLOGY) 

Employees of the Research Institute for Protective Technologies, Nuclear, Biological and Chemical Protection (WIS) inspect a dummy sample which is contaminated with a substance similar to the chemical weapon Sarin, during a demonstration in Munster October 15, 2013. The state-owned WIS is a reference laboratory for the Organisation for the Prohibition of Chemical Weapons (OPCW). Picture taken October 15, 2013. REUTERS/Fabrizio Bensch (GERMANY - Tags: MILITARY SCIENCE TECHNOLOGY) 

A convoy of vehicles carrying United Nations inspectors leaves the Masna'a border crossing between Lebanon and Syria in eastern Bekaa region of Lebanon September 30, 2013. U.N. chemical weapons inspectors investigating allegations of chemical and biological weapons use during Syria's civil war left Damascus on Monday after their second mission in two months, witnesses said. REUTERS/Stringer (LEBANON - Tags: POLITICS CIVIL UNREST) 

A convoy of vehicles carrying United Nations inspectors leaves the Masna'a border crossing between Lebanon and Syria in eastern Bekaa region of Lebanon September 30, 2013. U.N. chemical weapons inspectors investigating allegations of chemical and biological weapons use during Syria's civil war left Damascus on Monday after their second mission in two months, witnesses said. REUTERS/Stringer (LEBANON - Tags: POLITICS CIVIL UNREST) 

U.N. vehicles transport a team of United Nations chemical weapons experts in Damascus September 30, 2013. U.N. chemical weapons inspectors investigating allegations of chemical and biological weapons use during Syria's civil war left Damascus on Monday after their second mission in two months, witnesses said. REUTERS/Khaled al-Hariri (SYRIA - Tags: POLITICS CONFLICT HEALTH CIVIL UNREST) 

U.N. vehicles transport a team of United Nations chemical weapons experts in Damascus September 30, 2013. U.N. chemical weapons inspectors investigating allegations of chemical and biological weapons use during Syria's civil war left Damascus on Monday after their second mission in two months, witnesses said. REUTERS/Khaled al-Hariri (SYRIA - Tags: POLITICS CONFLICT HEALTH CIVIL UNREST) 

U.N. vehicles transport a team of United Nations chemical weapons experts in Damascus September 30, 2013. U.N. chemical weapons inspectors investigating allegations of chemical and biological weapons use during Syria's civil war left Damascus on Monday after their second mission in two months, witnesses said. REUTERS/Khaled al-Hariri (SYRIA - Tags: POLITICS CONFLICT CIVIL UNREST) 

Ake Sellstrom (2nd L), the head of a U.N. chemical weapons investigation team, leaves a hotel in Damascus September 30, 2013. U.N. chemical weapons inspectors investigating allegations of chemical and biological weapons use during Syria's civil war left Damascus on Monday after their second mission in two months, witnesses said. REUTERS/Khaled al-Hariri (SYRIA - Tags: POLITICS CONFLICT HEALTH CIVIL UNREST) 

Ake Sellstrom, the head of a U.N. chemical weapons investigation team, leaves a hotel in Damascus September 30, 2013. U.N. chemical weapons inspectors investigating allegations of chemical and biological weapons use during Syria's civil war left Damascus on Monday after their second mission in two months, witnesses said. REUTERS/Khaled al-Hariri (SYRIA - Tags: POLITICS CONFLICT HEALTH CIVIL UNREST) 

Ake Sellstrom (R), the head of a U.N. chemical weapons investigation team, leaves a hotel in Damascus September 30, 2013. U.N. chemical weapons inspectors investigating allegations of chemical and biological weapons use during Syria's civil war left Damascus on Monday after their second mission in two months, witnesses said. REUTERS/Khaled al-Hariri (SYRIA - Tags: POLITICS CONFLICT CIVIL UNREST) 

Ake Sellstrom (R), the head of a U.N. chemical weapons investigation team, leaves a hotel in Damascus September 30, 2013. U.N. chemical weapons inspectors investigating allegations of chemical and biological weapons use during Syria's civil war left Damascus on Monday after their second mission in two months, witnesses said. REUTERS/Khaled al-Hariri (SYRIA - Tags: POLITICS CONFLICT CIVIL UNREST) 

A member of the team of United Nations chemical weapons experts leaves a hotel in Damascus September 30, 2013. U.N. chemical weapons inspectors investigating allegations of chemical and biological weapons use during Syria's civil war left Damascus on Monday after their second mission in two months, witnesses said. REUTERS/Khaled al-Hariri (SYRIA - Tags: POLITICS CONFLICT HEALTH) 

A member of the team of United Nations chemical weapons experts leaves a hotel in Damascus September 30, 2013. U.N. chemical weapons inspectors investigating allegations of chemical and biological weapons use during Syria's civil war left Damascus on Monday after their second mission in two months, witnesses said. REUTERS/Khaled al-Hariri (SYRIA - Tags: POLITICS CONFLICT CIVIL UNREST) 

Brazilian army soldiers wearing chemical suits participate in an anti-terror simulation exercise as part of the preparation for the upcoming 2013 FIFA Confederations Cup in Brasilia. May 22, 2013. About 100 soldiers took part in the exercise which include preventive strikes against chemical, biological and radiological weapons conducted around Mane Garrincha National Stadium, according to an official statement. REUTERS/Ueslei Marcelino (BRAZIL - Tags: SPORT SOCCER MILITARY) 

Brazilian army soldiers wearing chemical suits participate in an anti-terror simulation exercise as part of the preparation for the upcoming 2013 FIFA Confederations Cup in Brasilia. May 22, 2013. About 100 soldiers took part in the exercise which include preventive strikes against chemical, biological and radiological weapons conducted around Mane Garrincha National Stadium, according to an official statement. REUTERS/Ueslei Marcelino (BRAZIL - Tags: SPORT SOCCER MILITARY TPX IMAGES OF THE DAY) 

Brazilian army soldiers wearing chemical suits participate in an anti-terror simulation exercise as part of the preparation for the upcoming 2013 FIFA Confederations Cup in Brasilia. May 22, 2013. About 100 soldiers took part in the exercise which include preventive strikes against chemical, biological and radiological weapons conducted around Mane Garrincha National Stadium, according to an official statement. REUTERS/Ueslei Marcelino (BRAZIL - Tags: SPORT SOCCER MILITARY) 

Brazilian army soldiers wearing chemical suits participate in an anti-terror simulation exercise as part of the preparation for the upcoming 2013 FIFA Confederations Cup in Brasilia. May 22, 2013. About 100 soldiers took part in the exercise which include preventive strikes against chemical, biological and radiological weapons conducted around Mane Garrincha National Stadium, according to an official statement. REUTERS/Ueslei Marcelino (BRAZIL - Tags: SPORT SOCCER MILITARY) 

Brazilian army soldiers wearing chemical suits participate in an anti-terror simulation exercise as part of the preparation for the upcoming 2013 FIFA Confederations Cup in Brasilia. May 22, 2013. About 100 soldiers took part in the exercise which include preventive strikes against chemical, biological and radiological weapons conducted around Mane Garrincha National Stadium, according to an official statement. REUTERS/Ueslei Marcelino (BRAZIL - Tags: SPORT SOCCER MILITARY) 

A Brazilian army soldier wearing a chemical suit participates in an anti-terror simulation exercise as part of the preparation for the upcoming 2013 FIFA Confederations Cup in Brasilia. May 22, 2013. About 100 soldiers took part in the exercise which include preventive strikes against chemical, biological and radiological weapons conducted around Mane Garrincha National Stadium, according to an official statement. REUTERS/Ueslei Marcelino (BRAZIL - Tags: SPORT SOCCER MILITARY) 

A Brazilian army soldier wearing a chemical suit participates in an anti-terror simulation exercise as part of the preparation for the upcoming 2013 FIFA Confederations Cup in Brasilia. May 22, 2013. About 100 soldiers took part in the exercise which include preventive strikes against chemical, biological and radiological weapons conducted around Mane Garrincha National Stadium, according to an official statement. REUTERS/Ueslei Marcelino (BRAZIL - Tags: SPORT SOCCER MILITARY) 

Brazilian army soldiers wearing chemical suits participate in an anti-terror simulation exercise as part of the preparation for the upcoming 2013 FIFA Confederations Cup in Brasilia. May 22, 2013. About 100 soldiers took part in the exercise which include preventive strikes against chemical, biological and radiological weapons conducted around Mane Garrincha National Stadium, according to an official statement. REUTERS/Ueslei Marcelino (BRAZIL - Tags: SPORT SOCCER MILITARY) 

Brazilian army soldiers wearing chemical suits participate in an anti-terror simulation exercise as part of the preparation for the upcoming 2013 FIFA Confederations Cup in Brasilia. May 22, 2013. About 100 soldiers took part in the exercise which include preventive strikes against chemical, biological and radiological weapons conducted around Mane Garrincha National Stadium, according to an official statement. REUTERS/Ueslei Marcelino (BRAZIL - Tags: SPORT SOCCER MILITARY) 

A Brazilian army soldier wearing a chemical suit participates in an anti-terror simulation exercise as part of the preparation for the upcoming 2013 FIFA Confederations Cup in Brasilia. May 22, 2013. About 100 soldiers took part in the exercise which include preventive strikes against chemical, biological and radiological weapons conducted around Mane Garrincha National Stadium, according to an official statement. REUTERS/Ueslei Marcelino (BRAZIL - Tags: SPORT SOCCER MILITARY) 

Brazilian army soldiers wearing chemical suits participate in an anti-terror simulation exercise as part of the preparation for the upcoming 2013 FIFA Confederations Cup in Brasilia. May 22, 2013. About 100 soldiers took part in the exercise which include preventive strikes against chemical, biological and radiological weapons conducted around Mane Garrincha National Stadium, according to an official statement. REUTERS/Ueslei Marcelino (BRAZIL - Tags: SPORT SOCCER MILITARY) 

Brazilian army soldiers wearing chemical suits participate in an anti-terror simulation exercise as part of the preparation for the upcoming 2013 FIFA Confederations Cup in Brasilia. May 22, 2013. About 100 soldiers took part in the exercise which include preventive strikes against chemical, biological and radiological weapons conducted around Mane Garrincha National Stadium, according to an official statement. REUTERS/Ueslei Marcelino (BRAZIL - Tags: SPORT SOCCER MILITARY) 

Students exit a building where they were introduced to the effects of tear gas as part of their chemical, biological, and radiological training during a summer military boot camp in Ansan, south of Seoul August 8, 2012. Over 1,000 students and civilians are attending attending the boot camp training courses, running from July till August at the Blue Dragon Camp operated by retired marines. REUTERS/Lee Jae-Won (SOUTH KOREA - Tags: EDUCATION SOCIETY MILITARY) 

A paratrooper from Chosen Company of the 3rd Battalion (Airborne), 509th Infantry walks up the staircase of an Afghan house on a search for weapons after finding contraband ammunition in a home, while on a helicopter assault mission to improve their biological database of fighting aged males, near the town of Ahmad Khel in Afghanistan's Paktiya Province July 16, 2012. Picture taken July 16. REUTERS/Lucas Jackson (AFGHANISTAN - Tags: CIVIL UNREST MILITARY) 

An Afghan boy peeks out of his home to watch a paratrooper from Chosen Company of the 3rd Battalion (Airborne), 509th Infantry walking past while on a helicopter assault mission to improve their biological database of fighting aged males, near the town of Ahmad Khel in Afghanistan's Paktiya Province July 16, 2012. Picture taken July 16. REUTERS/Lucas Jackson (AFGHANISTAN - Tags: CIVIL UNREST MILITARY) 

A paratrooper from Chosen Company of the 3rd Battalion (Airborne), 509th Infantry searches an abandoned qalat for weapons during a mission to improve the biological database of men in Afghanistan's Paktiya Province July 12, 2012. REUTERS/Lucas Jackson (AFGHANISTAN - Tags: CIVIL UNREST MILITARY) 

Personnel from Japan's Self-Defense Forces in protective gear take part in a nuclear, biological and chemical weapons (NBC) exercise, held as part of a drill for the Proliferation Security Initiative (PSI) Air Interdiction Exercise "Pacific Shield 12", at New Chitose airport in Chitose on Japan's northern island of Hokkaido July 4, 2012. Japan, Australia, South Korea and Singapore are taking part in the three-day drill to improve their capability to prevent the possible transport of weapons of mass destruction by air. REUTERS/Issei Kato (JAPAN - Tags: MILITARY POLITICS) 

Japan's police officers in protective gear take part in a nuclear, biological and chemical weapons (NBC) exercise, held as part of a drill for the Proliferation Security Initiative (PSI) Air Interdiction Exercise "Pacific Shield 12", at New Chitose airport in Chitose on Japan's northern island of Hokkaido July 4, 2012. Japan, Australia, South Korea and Singapore are taking part in the three-day drill to improve their capability to prevent the possible transport of weapons of mass destruction by air. REUTERS/Issei Kato (JAPAN - Tags: MILITARY POLITICS) 

Personnel from Japan's Self-Defense Forces in protective gear take part in a nuclear, biological and chemical weapons (NBC) exercise, held as part of a drill for the Proliferation Security Initiative (PSI) Air Interdiction Exercise "Pacific Shield 12", at New Chitose airport in Chitose on Japan's northern island of Hokkaido July 4, 2012. Japan, Australia, South Korea and Singapore are taking part in the three-day drill to improve their capability to prevent the possible transport of weapons of mass destruction by air. REUTERS/Issei Kato (JAPAN - Tags: MILITARY POLITICS) 

A Singapore Armed Forces' Chemical, Biological, Radiological and Explosives (CBRE) unit member takes part in a nuclear, biological and chemical weapons (NBC) exercise, held as part of a drill for the Proliferation Security Initiative (PSI) Air Interdiction Exercise "Pacific Shield 12", at New Chitose airport in Chitose on Japan's northern island of Hokkaido July 4, 2012. Japan, Australia, South Korea and Singapore are taking part in the three-day drill to improve their capability to prevent the possible transport of weapons of mass destruction by air. REUTERS/Issei Kato (JAPAN - Tags: MILITARY POLITICS) 

Singapore Armed Forces' Chemical, Biological, Radiological and Explosives (CBRE) unit members in protective gear take part in a nuclear, biological and chemical weapons (NBC) exercise, held as a part of a drill for the Proliferation Security Initiative (PSI) Air Interdiction Exercise "Pacific Shield 12", at New Chitose airport in Chitose on Japan's northern island of Hokkaido July 4, 2012. Japan, Australia, South Korea and Singapore are taking part in the three-day drill to improve their capability to prevent possible transport of weapons of mass destruction by air. REUTERS/Issei Kato (JAPAN - Tags: MILITARY POLITICS) 

South Korean soldiers in protective gear take part in a nuclear, biological and chemical weapons (NBC) exercise, held as a part of a drill for the Proliferation Security Initiative (PSI) Air Interdiction Exercise "Pacific Shield 12", at New Chitose airport in Chitose on Japan's northern island of Hokkaido July 4, 2012. Japan, Australia, South Korea and Singapore are taking part in the three-day drill to improve their capability to prevent possible transport of weapons of mass destruction by air. REUTERS/Issei Kato (JAPAN - Tags: MILITARY POLITICS) 

A South Korean soldier (C) leaves off his protective gear as Japan's Self-Defense Forces personnel look on, as they takes part in a nuclear, biological and chemical weapons (NBC) exercise, held as a part of a drill for the Proliferation Security Initiative (PSI) Air Interdiction Exercise "Pacific Shield 12", at New Chitose airport in Chitose on Japan's northern island of Hokkaido July 4, 2012. Japan, Australia, South Korea and Singapore are taking part in the three-day drill to improve their capability to prevent possible transport of weapons of mass destruction by air. REUTERS/Issei Kato (JAPAN - Tags: MILITARY POLITICS) 

South Korean soldiers in protective gear take part in a nuclear, biological and chemical weapons (NBC) exercise, held as a part of a drill for the Proliferation Security Initiative (PSI) Air Interdiction Exercise "Pacific Shield 12", at New Chitose airport in Chitose on Japan's northern island of Hokkaido July 4, 2012. Japan, Australia, South Korea and Singapore are taking part in the three-day drill to improve their capability to prevent possible transport of weapons of mass destruction by air. REUTERS/Issei Kato (JAPAN - Tags: MILITARY POLITICS) 

A South Korean soldier in protective gear takes part in a nuclear, biological and chemical weapons (NBC) exercise, held as a part of a drill for the Proliferation Security Initiative (PSI) Air Interdiction Exercise "Pacific Shield 12", at New Chitose airport in Chitose on Japan's northern island of Hokkaido July 4, 2012. Japan, Australia, South Korea and Singapore are taking part in the three-day drill to improve their capability to prevent possible transport of weapons of mass destruction by air. REUTERS/Issei Kato (JAPAN - Tags: MILITARY POLITICS) 

South Korean soldiers in protective gear take part in a nuclear, biological and chemical weapons (NBC) exercise, held as a part of a drill for the Proliferation Security Initiative (PSI) Air Interdiction Exercise "Pacific Shield 12", at New Chitose airport in Chitose on Japan's northern island of Hokkaido July 4, 2012. Japan, Australia, South Korea and Singapore are taking part in the three-day drill to improve their capability to prevent possible transport of weapons of mass destruction by air. REUTERS/Issei Kato (JAPAN - Tags: MILITARY POLITICS) 

South Korean soldiers in protective gear take part in a nuclear, biological and chemical weapons (NBC) exercise, held as a part of a drill for the Proliferation Security Initiative (PSI) Air Interdiction Exercise "Pacific Shield 12", at New Chitose airport in Chitose on Japan's northern island of Hokkaido July 4, 2012. Japan, Australia, South Korea and Singapore are taking part in the three-day drill to improve their capability to prevent possible transport of weapons of mass destruction by air. REUTERS/Issei Kato (JAPAN - Tags: MILITARY POLITICS)