The UN Security Council will vote on two rival resolutions regarding Syria on Saturday.

One drafted by France calls for stopping the aerial bombardment of Aleppo. The Security Council will then move to a second vote on the Russian-drafted text that calls for a ceasefire, but does not mention ending the airstrikes. But Russia does support UN envoy Staffan de Mistura's plan to allow rebels to leave the city with their weapons.

US Secretary of State John Kerry said Russian and Syrian actions such as bombing hospitals cry out for a war crimes investigation. Russia accuses the US of supporting terrorists by backing rebel groups. Its foreign ministry spokeswoman Maria Zakharovathe said the call for an investigation is an attempt to distract from the failure of the earlier US-Russia brokered ceasefire. The spokeswoman said "war crimes also weigh on the shoulders of American officials."