What has the UN report into war crimes in Syria said?
A report by UN investigators found war crimes had been committed in the Syrian conflict in Aleppo.
Government forces loyal to Assad used Syrian helicopters to unleash toxic chlorine bombs on Aleppo throughout 2016. At least 5,000 pro-government forces also encircled eastern Aleppo in a "surrender or starve" tactic, it said.
Opposition groups fired shells on to western Aleppo, which was controlled by the government, and killed and injured dozens of civilians. They also prevented civilians from leaving eastern Aleppo, turning them into "human shields".