IS foreign militants leave Syria's Raqqa under evacuation deal

The move comes as part of a deal that signals the imminent capture of the city, but flouts earlier US protests of negotiating safe exits for the extremist group.

"A portion of the foreigners have left," said Omar Alloush, a senior member of the Raqqa Civil Council, when asked about the deal announced on Saturday,

He could not confirm how many fighters had left the city or where they had gone.

"They took civilians as human shields and left," he added.

The US-led coalition and local officials said on Saturday only Syrian IS militants and civilians will be allowed to evacuate the city. Foreign militants were excluded from the deal, according to the coalition.

The tribal leaders said they appealed to the coalition and the US-backed Syrian Democratic Forces to allow the evacuation of local Islamic State fighters to stem further violence.

"Because our aim is liberation not killing, we appealed to the SDF to arrange for the local fighters and secure their exit to outside of the city, with our guarantees," the tribal leaders said in a statement reported by AP.

But Allouch told AFP that subsequently a deal was reached for foreign IS militants to leave Raqqa.

The US-backed SDF, an alliance of Kurdish and Arab fighters, has been battling since June to capture Raqqa.

They hold around 90 percent of the city, but have struggled to take remaining IS positions over fears of large numbers of civilians being held as human shields.

Raqqa was once the de facto Syrian capital of the Islamic State group's self-styled "caliphate" straddling Syria and Iraq.

Its loss would be the latest in a string of blows to the group, which has ceded large swathes of territory including Iraq's second city Mosul.