More than 60 killed in Aleppo in 24 hours

Airstrikes on the rebel-held part of Syria's contested city of Aleppo have killed 20 people and brought down at least one residential building.

The new violence on Thursday brings the death toll in the deeply divided city to at least 61 killed in the past 24 hours.

Three children were among those killed in the latest airstrike.

It follows a wave of night time airstrikes on an internationally-backed hospital which killed at least 27 people, including six medical staff and three children.

The Syrian Civil Defence, a volunteer first-responders agency whose members went to the scene of the attack, say the new airstrikes hit in the Bustan al-Qasr neighborhood and that rescue works is underway.

But the group, also known as the White Helmets, said they were exhausted by the escalation in violence.

"We were still working on the airstrikes from last night in the Sukkari neighbourhood," one volunteer said.

An upsurge in fighting in Aleppo, Syria's pre-war commercial hub, has killed at least 186 people since Friday.

The International Committee of the Red Cross is warning that Aleppo is on the brink of a humanitarian disaster as a result of renewed fighting, adding that millions are at a grave risk.

The organisation said that contingency food and medical aid are expected to run out soon and warned that an escalation in fighting means that they cannot be replenished.

Agencies contributed to this report