GENEVA, Sept 14 (Reuters) – Syria is still unsafe for the return of refugees a decade after its conflict began, U.N. war crimes investigators said on Tuesday, documenting worsening violence and rights violations including arbitrary detention by government forces. “The Commission has continued to document not only torture and sexual violence in detention but also custodial deaths and enforced disappearances,” a press release said. The war, which spiralled out of an uprising against President Bashar al-Assad’s rule, sparked the world’s biggest refugee crisis. It also criticised the unlawful internment of thousands of women and children held on suspicion of Islamic State links in camps in areas controlled by the U.S.-backed Syrian Democratic Forces, saying they had no legal recourse. They had “been left to fend for themselves in conditions that may amount to cruel or inhuman treatment”.