A fighter from SDF flies a drone in western Raqqa province, Syria June 18, 2017.
Kurdish fighters from the People's Protection Units (YPG) stand in a house in Raqqa, Syria June 21, 2017.
Graduates of a U.S.-trained police force, which expects to be deployed in Raqqa, salute during a graduation ceremony near Ain Issa village, north of Raqqa, Syria, June 17, 2017.
Women fighters from SDF are seen in the western of Raqqa province, Syria June 18, 2017.
Kurdish fighters from the People's Protection Units (YPG) stand outside a house in Raqqa, Syria June 21, 2017.
Female Kurdish fighters from the People's Protection Units (YPG) sit in a house in Raqqa, Syria, June 15, 2017.
Members of Roj Mine Control Organization destroy explosive devices planted by Islamic State militants near Ain Issa village north of Raqqa, Syria, June 20, 2017.
A fighter from SDF sits in his vehicle in the western of Raqqa province,Syria June 18, 2017.
Graduates of a U.S.-trained police force, which expects to be deployed in Raqqa, dance during a graduation ceremony near Ain Issa village, north of Raqqa, Syria, June 17, 2017.
A civilian riding a bicycle gestures towards a vehicle of the Syrian Democratic Forces (SDF) fighters in the Raqqa's al-Sanaa industrial neighbourhood, Syria June 14, 2017. Picture taken June 14, 2017.
A Kurdish fighter from the People's Protection Units (YPG) carries ammunition in Raqqa, Syria June 21, 2017. REUTERS/Goran Tomasevic .
People cross a makeshift ladder in a village near Raqqa after a bridge was destroyed in fighting between the U.S.-led coalition and Islamic State, Raqqa, Syria June 16, 2017.
A Syrian Democratic Forces (SDF) fighter carries his weapon as he stands near Raqqa city, Syria June 14, 2017.
A member of Roj Mine Control Organization searches for mines and explosive devices planted by Islamic State militants to disarm them near Ain Issa village north of Raqqa, Syria, June 20, 2017.
Kurdish fighters from the People's Protection Units (YPG) extinguish a fire in a wheat field burned during clashes with Islamic State militants in Raqqa, Syria, June 15, 2017.
A female Kurdish fighter from the People's Protection Units (YPG) fires a long range sniper rifle at Islamic State militants in Raqqa, Syria June 18, 2017.
Kurdish fighters from the People's Protection Units (YPG) fires rifles at a drone operated by Islamic State militants in Raqqa, Syria June 16, 2017.
The road to Raqqa
The U.S.-backed Syrian Democratic Forces has seized territory to the north, east and west of Raqqa in their assault to capture Islamic State's de facto