The incident took place near the town of Al-Shahil in the southeast of oil-rich Deir al-Zor province that borders Iraq It came as the SDF presses on with efforts to retake the last small area of territory held in Syria by Daesh NEAR BAGHOUZ, Syria: A car bombing killed 20 people near the main base of US-backed Syrian forces on Thursday as fighters tried to negotiate the release of civilians still trapped in Daesh’s last redoubt. As the Syrian Democratic Forces pressed the last extremist diehards the car bomb killed 14 oil workers and six of the Kurdish-led alliance’s conscripts near the Omar oil field which is uses as its main base in the region, the US-backed group and a monitor said. SDF spokesman Adnan Afrin said the blast in the village of Shheel, some 100 kilometers north of Baghouz, was another example of Daesh cells attacking its fighters behind the front line. The SDF are working toward evacuating civilians remaining in the holdout in east Syria, so they can retake the last scrap of the dying Daesh “caliphate” whether through an assault or a surrender deal. The extremists overran large parts of Syria and neighboring Iraq in 2014, but several offensives have retaken all but half a square kilometer (a fifth of a square mile) of the territory in the eastern Syrian village of Baghouz. A spokesman for the US-led coalition fighting Daesh said international forces “continue to support the SDF as they negotiate having innocent civilians released” and their captured fighters returned. A day after hundreds of people were evacuated from the last Daesh remnant, more than 50 trucks on Thursday returned near empty from Baghouz to SDF territory, an AFP correspondent said. “We couldn’t enter Baghouz,” said a man who had accompanied the convoy. “We got to an SDF point and we found around 15 people — women and children including a French woman and an Egyptian woman. We took them,” he said. “The fighters asked us to go back tomorrow at 8 am.” Thousands of people have escaped Daesh territory in recent weeks, but the flow slowed to a trickle at the weekend, before Wednesday’s first batch of evacuees. Paul Bradley, from the Free Burma Rangers volunteer group, said people fleeing painted a grim picture of life inside. “They showed us this bread that’s basically mashed up wheat with water burnt on both sides, $16 a kilo,” he said. SDF spokesman Afrin said most of those trucked out on Wednesday were civilians, but they also included Daesh fighters. 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 extremists 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 Daesh fighters.” It said there were “reports of a deal” but the details were unclear. At the height of its rule, Daesh imposed its brutal ideology on a territory roughly the size of the United Kingdom, attracting thousands of supporters from abroad. But the extremists have since lost almost all their territory, and hundreds of foreigners suspected of being Daesh fighters, as well as related women and children, are being held by the SDF. Other foreign members have been killed. A top French extremist, who voiced an audio recording claiming responsibility for the November 2015 attacks in Paris, was killed in an overnight airstrike, security sources told AFP on Thursday. Fabien Clain, who is believed to have gone to Syria in March 2015, was killed in Baghouz, they said. Across the border, security officials in Iraq said the SDF handed over 130 Iraqi extremsts to Baghdad on Thursday, but SDF spokesman Mustefa Bali denied the claim. Syria’s Kurds have long demanded the repatriation of foreigners accused of belonging to Daesh in their custody, but their home countries have been reluctant. US President Donald Trump said Wednesday he was barring a US-born former Daesh propagandist from returning home from Syria, where the conflict has killed more than 360,000 people and displaced millions since 2011. Secretary of State Mike Pompeo said Thursday that the diplomatic status of the father of Alabama woman Hoda Muthana means she is not a US citizen. It came after a lawyer for the family of a teenager who fled London to join the extremists when she was 15 said Britain was revoking her citizenship. Shamima Begum, 19, at the weekend gave birth to her third child. Two previous children died at an early age.