All military action in eastern Aleppo has ended and the Syrian government has re-established control over the former rebel-held area, Russia's UN ambassador has said.
Vitaly Churkin spoke near the end of an emergency meeting of the UN Security Council, saying "according to the latest information that we received in the last hour, military actions in eastern Aleppo are over".
He said that as a result, "there is no issue of some cessation of hostilities, or some special humanitarian operation".
He added that "the Syrian government has re-established control over eastern Aleppo".
Mr Churkin said earlier that "all militants" and members of their families, as well as those wounded in the fighting, "currently are going through agreed corridors in directions that they have chosen themselves voluntarily, including toward Idlib", a rebel stronghold.
The evacuation of the remaining rebels would mark a major victory for President Bashar Assad and return Syria's largest city to full government control for the first time since rebels seized the eastern half in 2012.
Later, the United Nations called for immediate access to eastern Aleppo to confirm Russia's announcement and to monitor the evacuation of civilians and the withdrawal of opposition fighters.
The UN envoy for Syria, Staffan de Mistura, said after the emergency meeting of the UN Security Council that armed groups are still estimated to control up to 5 sq km (1.9 sq miles) in eastern Aleppo.
He said the UN's main concern is the up to 50,000 civilians still believed to be in eastern Aleppo.
He said an estimated 1,500 fighters are still there, about 30% of them from the al Qaida linked Fatah al-Sham Front, previously known as the Nusra Front. Mr De Mistura said such figures must be taken "very cautiously" because the UN is not there.
He said it is not clear whether the fighters are leaving with their weapons, which was an issue being discussed.
Mr De Mistura said the UN is insisting that civilians who want to go with the fighters to rebel-held Idlib province be allowed to do so. He also expressed concern that Idlib could become the next target of the Syrian military.