Russia vetoed a French-drafted United Nations Security Council resolution on Saturday that would have demanded an immediate end to airstrikes and military flights over the Syrian city of Aleppo. It also called for a truce and humanitarian aid access throughout Syria.

It is the fifth time Russia has vetoed a UN resolution on Syria during the more than five-year conflict. The previous four times Moscow was backed by Beijing, but on Saturday China abstained from the vote.

Louis Charbonneau, UN director at Human Rights Watch, criticized the veto. "Russia has once again abused its veto privilege and sabotaged the UN Security Council, this time stonewalling efforts to stop the vicious assault on east Aleppo's civilians," she said.

"Today's vote is a stark reminder of the urgent need for permanent members of the Security Council to shelve the veto in situations of mass atrocities, an idea supported by a vast majority of countries around the world."

Charbonneau said the ball is now in the court of the UN General Assembly, urging it to hold an emergency meeting and "demand an end to unlawful attacks on civilians in Aleppo, 100,000 of whom are children, and explore avenues for accountability."

A man walks on the rubble of damaged buildings after an airstrike on the rebel held al-Qaterji neighbourhood of Aleppo, Syria. For the fifth time during the conflict, Russia has vetoed a UN resolution on Syria. (Abdalrhman Ismail/Reuters)

Angola also abstained from the vote, while Venezuela joined Russia in voting against the text. Eleven of the 15 council members voted in favour of the draft resolution.

A UN resolution needs nine votes in favour and no vetoes to be adopted.

The veto powers are the United States, France, Britain, Russia and China.

UNICEF's representative in Syria called for an end to violence Saturday, saying the situation in eastern Aleppo is "terribly dire."

"Lots of schools and of hospitals have been hit. We understand that there are only 30 doctors there. We have information that at least over 100 children have been killed," said Hanaa Singer, of the UN children's agency.

"We hear that because of the lack of services and lack of health facilities that ... doctors can't cope with all the cases, and some children in dire situations are left to die."