A British volunteer fighter of Syrian Democratic Forces runs for cover to avoid sniper fire of Islamic State militants, at the frontline in Raqqa, Syria October 7, 2017.
Fighters of Syrian Democratic Forces walk along a street in Raqqa, Syria October 17, 2017.
Fighters of Syrian Democratic Forces ride atop an armoured vehicle after Raqqa was liberated from the Islamic State militants, in Raqqa, Syria October 17, 2017.
A female sniper of Syrian Democratic Forces looks through the scope of her rifle as she takes up a position opposite the National Hospital where the Islamic State militants are holed up at the frontline in Raqqa, Syria October 16, 2017.
Fighters of Syrian Democratic Forces raise a white flag near the National Hospital complex where the Islamic State militants are holed up, at the frontline in Raqqa, Syria October 16, 2017.
Syrian Democratic Forces (SDF) fighters ride atop military vehicles as they celebrate victory in Raqqa, Syria, October 17, 2017. REUTERS/Erik De Castro
Fighters of the Syrian Democratic Forces (SDF) dance along a street in Raqqa, Syria October 18, 2017.
Military vehicles are seen in Raqqa, Syria, October 16, 2017.
Fighters of Syrian Democratic Forces raise a white flag on top of a building near the National Hospital where the Islamic State militants are holed up at the frontline in Raqqa, Syria October 16, 2017.
A fighter of Syrian Democratic Forces inspects an RPG at his position inside a building at the frontline in Raqqa, Syria October 16, 2017.
Fighters of Syrian Democratic Forces gesture the "V" sign at the frontline in Raqqa, Syria October 16, 2017.
A female fighter of Syrian Democratic Forces is seen in Raqqa, Syria October 17, 2017.
A civilian prays after she was rescued by fighters of Syrian Democratic Forces from the stadium after Raqqa was liberated from the Islamic State militants in Raqqa, Syria, October 17, 2017.
Fighters of Syrian Democratic Forces take a selfie at the stadium after it was retaken from the Islamic State militants, in Raqqa, Syria October 17, 2017.
Flags of Syrian Democratic Forces are placed at Naim roundabout after the liberation, in Raqqa, Syria October 18, 2017.
Fighters of Syrian Democratic Forces gesture the "V" sign in Raqqa, Syria October 17, 2017.
REUTERS/Rodi Said
Fighters of Syrian Democratic Forces ride atop of an armoured vehicle after Raqqa was liberated from the Islamic State militants, in Raqqa, Syria October 17, 2017.
Fighters of the Syrian Democratic Forces (SDF) sit inside a vehicle in Raqqa, Syria, October 16, 2017.
The ruins of a shopping centre are seen in Raqqa, Syria October 18, 2017, after Raqqa was liberated by the Syrian Democratic Forces.
Female fighters from Syrian Democratic Forces (SDF) react in Raqqa, Syria, October 16, 2017.
Fighters of Syrian Democratic Forces walk along a road past destroyed vehicles at the frontline in Raqqa, Syria October 16, 2017.
Syrian Democratic Forces (SDF) fighters ride atop of military vehicles as they celebrate victory in Raqqa, Syria, October 17, 2017.
Fighters of Syrian Democratic Forces place flags at Naim Square after liberating Raqqa, Syria October 18, 2017.
Islamic State's capital Raqqa falls
U.S.-backed militias in Syria declare victory over Islamic State in its capital Raqqa, raising flags over the last jihadist footholds after a four-month battle.