The dead included at least two children, a dentist and the only pediatrician left in rebel-held areas of the city, civil defense volunteers told AFP news agency. According to the Syrian Observatory for Human Rights 49 civilians have been killed by Assad air strikes during the past 6 days.

Speaking after briefing the Security Council on the peace process, the United Nations (UN) Envoy to Syria, Staffan de Mistura said a partial truce agreed in February was “barely alive” and urged the United States and Russia to intervene “at the highest level” to save struggling peace talks in Geneva.

Several reports reveal that the Syrian army, backed by Russian air forces, prepares for a major offensive in Aleppo.

Speaking on Wednesday, Mr. de Mistura said the fragile “cessation of hostilities” “could collapse any time”. He added that over the past 48 hours an average of one Syrian had been killed every 25 minutes and one wounded every 13 minutes.

De Mistura said there will be another round of peace talks before July: “There are still major differences on the major issues, but there is movement on certain areas where there was not before”.

Yesterday, the Russian Deputy Foreign Minister Mikhail Bogdanov was quoted saying peace talks would resume by May 10. But later on, a spokeswoman for Staffan de Mistura said in an email that talk about May 10 was speculation and that no date had been set.

“How can you have substantial talks when you have only news about bombing and shelling?” de Mistura said earlier today.