A Kurdish politician captured by Turkish-backed Syrian forces was pulled by the hair and beaten with a blunt object before being shot in the head and body at close range, a post-mortem report shows. Hevrin Khalaf, secretary general of the Future Syria Party, was caught in an ambush by Turkish-backed militias while travelling in northern Syria on Saturday. Kurdish authorities have accused Turkey’s Syrian allies of executing Khalaf, her driver, other civilians and captured soldiers. Accusations of atrocities in Turkey's week-old offensive against Kurdish forces in north-east Syria are mounting. "It has been very difficult to verify a lot of things," Sara Kayyali, Syria researcher for Human Rights Watch, told <em>The National</em>. "There has been a lot of propaganda from all sides around what's happening. It’s difficult to get an understanding." Ms Kayyali said there was evidence of extrajudicial executions, indiscriminate shelling and civilians being prevented from fleeing. “What we have found so far has been in line with what we anticipated would happen," she said. "It’s more or less what we expected. “What concerns us deeply is forces preventing people from fleeing the violence." Ms Kayyali said there was evidence of this being committed by both sides. She said continuous cross-border shelling by Turkey was “inherently indiscriminate” and had caused civilian deaths. Turkish media reported that towns on the Turkish side of the border had been shelled by Kurdish forces in the past week. On Thursday, Kurdish forces accused Ankara of using banned weapons to capture the town of Ras Al Ain, which they took before being pushed back by the Syrian Democratic Forces. "The Turkish aggression is using all available weapons against Ras Al Ain," Kurdish authorities said. They accused Ankara of firing napalm and white phosphorus – internationally outlawed weapons – and harming civilians. "We urge international organisations to send their teams to investigate some of the wounds sustained in attacks," Mustafa Bali, a spokesman for the Kurdish-dominated SDF, said on social media. "The medical facilities in north-east Syria lack expert teams." Ms Kayyali advised caution over the claims. “Reports of the use of white phosphorus or chemical weapons all show footage from prior conflicts,” she said.