Islamic State billboards are seen along a street in Raqqa, eastern Syria, which is controlled by the Islamic State, October 29, 2014. The billboard reads: "We will win despite the global coalition". REUTERS/Nour Fourat 

Residents walk along the Tal Abyad street market in central Raqqa, ahead of the upcoming Muslim Eid al-Adha holiday, October 3, 2014. REUTERS/Stringer 

Residents walk along the Tal Abyad street market in central Raqqa, ahead of the Muslim Eid al-Adha holiday, in Raqqa, October 3, 2014.REUTERS/Stringer 

Youths carry banners during a protest against the U.S. airstrikes on the Islamic State in Raqqa, September 26, 2014. The banners in Arabic read, "By the soul, by the blood, we sacrifice ourselves oh state. by the soul, by the blood, we sacrifice ourselves oh Baghdadi" (C),"Who did not die by Assad's planes, died by Saudi family planes, The planes became many, but the strikes are one" (L). REUTERS/Stringer 

Militant Islamist fighters take part in a military parade along the streets of northern Raqqa province, June 30, 2014. REUTERS/Stringer 

An Islamic State militant uses a loud-hailer to announce to residents of Tabqa city that Tabqa air base has fallen to Islamic State militants, in nearby Raqqa city, August 24, 2014. REUTERS/Stringer 

Residents drive and ride their vehicles through a street in central Raqqa, September 25, 2014. REUTERS/Stringer 

Fighters from Islamic State in Iraq and the Levant burn confiscated cigarettes in the city of Raqqa, April 2, 2014. REUTERS/Stringer 

Children play on a ride inside a park in Raqqa, September 18, 2014. REUTERS/Stringer 

A boy stands during a protest against the U.S. airstrikes on the Islamic State (IS) in Raqqa, September 26, 2014. REUTERS/Stringer 

Female school students wearing a full veil walk along a street in the northern province of Raqqa, March 31, 2014. REUTERS/Stringer 

Residents flee what activists say was an air strike by forces loyal to Syria's President Bashar al-Assad on Tal Abyad street market in central Raqqa, September 6, 2014. REUTERS/Stringer 

A boy turns his head while standing amongst others praying inside a mosque in Raqqa, September 26, 2014. REUTERS/Stringer 

Residents look at fabric inside a shop in Raqqa, September 18, 2014. REUTERS/Stringer 

An Islamic State militant stands next to residents as they hold pieces of wreckage from a Syrian war plane after it crashed in Raqqa, in northeast Syria, September 16, 2014. REUTERS/Stringer 

Militant Islamist fighters take part in a military parade along the streets of Syria's northern Raqqa province, June 30, 2014. REUTERS/Stringer 

Militant Islamist fighters waving flags, travel in vehicles as they take part in a military parade along the streets of Syria's northern Raqqa province, June 30, 2014. REUTERS/Stringer 

Men pray outside their shops in Raqqa, April 5, 2014.REUTERS/Stringer 

An Islamic State policeman controls traffic in Raqqa, September 18, 2014. REUTERS/Stringer 

Residents swim in the Euphrates River in Raqqa, July 3, 2014. REUTERS/Stringer 

Militant Islamist fighters ride horses as they take part in a military parade along the streets of Syria's northern Raqqa province, June 30, 2014.

REUTERS/Stringer 

A vendor sells traditional bread during the Muslim holy fasting month of Ramadan in Raqqa province, eastern Syria, which is controlled by the Islamic State, July 23, 2014. REUTERS/Stringer 

Veiled women walk past a billboard that carries a verse from Koran urging women to wear a hijab in the northern province of Raqqa, March 31, 2014. REUTERS/Stringer 

A militant Islamist fighter uses a mobile to film his fellow fighters taking part in a military parade along the streets of Syria's northern Raqqa province, June 30, 2014. REUTERS/Stringer 

Residents look at gold jewellery displayed at a shop window in Raqqa, September 18, 2014. REUTERS/Stringer 

A militant Islamist fighter waving a flag, cheers as he takes part in a military parade along the streets of Syria's northern Raqqa province, June 30, 2014. REUTERS/Stringer 

Children gesture as they stand on a street in Raqqa, September 18, 2014. REUTERS/Stringer 

Residents flee what activists say was an air strike by forces loyal to Syria's President Bashar al-Assad on Tal Abyad street market in central Raqqa, September 6, 2014. REUTERS/Stringer 

A resident inspects perfumes inside a shop in Raqqa, September 18, 2014. REUTERS/Stringer 

A member loyal to the Islamic State in Iraq and the Levant waves an ISIL flag in Raqqa, June 29, 2014.REUTERS/Stringer 

Militant Islamist fighters in military vehicles parade along the streets of Syria's northern Raqqa province, June 30, 2014.
REUTERS/Stringer 

A militant Islamist fighter gestures as he takes part in a military parade along the streets of Syria's northern Raqqa province, June 30, 2014. REUTERS/Stringer 

Residents rest by the Euphrates River in Raqqa, April 11, 2014. REUTERS/Nour Fourat 

A family sits in a pick-up truck in the Euphrates River in Raqqa, April 11, 2014. REUTERS/Nour Fourat 

Militant Islamist fighters on a tank take part in a military parade along the streets of northern Raqqa province, June 30, 2014. REUTERS/Stringer 

Veiled women sit as they chat in a garden in the northern province of Raqqa, March 31, 2014. REUTERS/Stringer 

A resident of Tabqa city touring the streets on a motorcycle waves an Islamist flag in celebration after Islamic State militants took over Tabqa air base, in nearby Raqqa city, August 24, 2014. REUTERS/Stringer