Syrian and foreign ISIL fighters have agreed to leave their one-time bastion Raqqa under an agreement brokered by tribal leaders to prevent more civilian deaths in the city.
Omar Alloush, an official of the Raqqa Civil Council, said a deal had been reached to allow fighters out of the city, which is on the verge of being captured by the US-backed Syrian Democratic Forces (SDF) after months of heavy fighting.
"Foreign fighters are included in the deal," he said.
The agreement comes after days of talks on a way for the SDF to secure the last areas of Raqqa held by ISIL while avoiding further civilian casualties.
Mr Alloush said as many as 500 ISIL fighters remained in the northern Syrian city.
"They have 400 hostages with them - women and children - in the national hospital," he said.
An activist group that reports on the city, Raqqa Is Being Slaughtered Silently, said on its Facebook page that dozens of buses had entered Raqqa overnight from the countryside to the north.
The Syrian Observatory for Human Rights, a British-based organisation that reports on the war, said Syrian ISIL fighters and their families had already left the city, and buses had arrived to evacuate remaining foreign fighters and their families.
The US-led coalition backing the SDF's drive to capture Raqqa had announced the evacuation deal earlier on Saturday, but said it would exclude foreign ISIL fighters.
The coalition said the arrangement was brokered by the Raqqa Civil Council, set up to run the city after it is liberated from ISIL, and local Arab tribal elders on October 12, and was "designed to minimise civilian casualties and purportedly excludes foreign Daesh terrorists".
However Mr Alloush insisted the agreement included non-Syrian militants.
"The foreign fighters have two choices: either surrender or be taken out" of the city, he said.
The activist group Raqqa Is Being Slaughtered Silently said on its Facebook page on Saturday that dozens of buses had entered the city overnight from the countryside to the north.
The Syrian Observatory for Human Rights, a Britain-based organisation that reports on the war, said Syrian ISIL fighters and their families had already left the city, and buses had arrived to evacuate remaining foreign fighters and their families.
Mr Alloush said the militants might be taken to Deir Ezzor, an eastern province where ISIL still holds territory despite suffering losses to separate offensives by the SDF and Syrian government forces.
The Syrian army, which is supported by Iran-backed militias and the Russian air force, declared another significant victory over ISIL in Deir Ezzor on Saturday, saying it had captured the town of Al Mayadeen.
The town near the Iraqi border had become a major base for ISIL militants as they were being driven out of Raqqa.
A Syrian military source said the militants in Al Mayadeen had suffered a "collapse" in their ranks.
Over the past few months many of the individuals which the US-led coalition has targeted have come from Al Mayadeen, coalition spokesman Ryan Dillon said.
The town lies south of Deir Ezzor city, the provincial capital, where Syrian and allied forces are also trying to oust the militants from a small pocket they still control.