A deadly car bombing claimed by the Islamic State group hit US-backed forces in east Syria Thursday as they tried to negotiate the release of civilians trapped in the jihadists' last sliver of territory, AFP reported.
The Syrian Democratic Forces (SDF) are working towards evacuating civilians remaining in the holdout, so they can polish off the dying IS "caliphate" whether through an assault or a surrender deal.
A spokesman for the US-led coalition fighting IS said international forces "continue to support the SDF as they negotiate having innocent civilians released" and their captured fighters returned.
As the SDF pressed the last IS diehards a car bomb killed 14 oil workers and six of the Kurdish-led alliance's conscripts near the Omar oil field which it uses as its main base in the region, the US-backed group and a monitor said.
IS claimed responsibility for the blast on Telegram, saying its fighters had planted and detonated the explosive-laden car.
Thousands of people have escaped IS territory in recent weeks, but the flow slowed to a trickle at the weekend, before Wednesday's first batch of evacuees.
On Thursday, the AFP reporter saw hundreds of people waiting in a screening area where the SDF have been questioning new arrivals in recent weeks, to separate out suspected jihadists from the civilians.
The Syrian Observatory for Human Rights, a Britain-based war monitor, said Wednesday that negotiations were being held "for the surrender of the last IS fighters".
It said there were "reports of a deal" but the details were unclear.