At least 16 people have been killed in a Syrian government air strike on a hospital in the city of Aleppo as the United Nations warned that a delicate ceasefire was crumbling.

The attack on the Al Quds hospital on Wednesday evening killed several medical staff and other civilians, including Dr Wasem Maaz, one of the last remaining pediatricians in the rebel-held part of the city.

Rescue workers were pulling bodies and survivors from the rubble of the building in the Sukkary neighbourhood into the evening and witnesses told Al Jazeera the number of dead was likely to rise.

Pictures seen by Al Jazeera showed rows of bloodied and charred bodies covered in plastic sheets. The images were too graphic to be published.

The attack was the latest in an intensification of government assaults on the city, with at least 100 civilians killed in air strikes, shelling and rocket fire since Friday.

“In the last 48 hours, we have had an average of one Syrian killed every 25 minutes, one Syrian wounded every 13 minutes,” the UN special envoy to Syria, Staffan de Mistura, said, warning that peace talks were almost out of steam.

On Tuesday, at least 35 people – including eight children – were killed in Aleppo in fighting between government forces and rebels, a monitoring group said.

The bloc representing the opposition at peace talks in Geneva, the High Negotiations Committee (HNC), on Wednesday threatened to boycott the next round of talks unless the government stopped its bombing campaign.

The HNC left formal negotiations last week, saying that it needed a “pause”, after at least 40,000 people fled fighting near Aleppo when government forces pressed on with an offensive against rebel fighters there.

A ceasefire unravelling

De Mistura on Thursday said that the government and the main opposition group remained far apart in their competing visions of a political transition, despite some common ground.

In a seven-page document issued at the end of the two-week round of talks, he said the two sides shared a view “that the transitional governance could include members of the present government and the opposition, independents and others”.

But the potential presence of Assad in such an arrangement has been a sticking point.

De Mistura called on Russia and the United States to intervene and revive the negotiations.

“I really fear that the erosion of the cessation is unravelling the fragile consensus around a political solution, carefully built over the last year,” de Mistura said in a briefing to the UN Security Council, which was obtained by the Associated Press news agency.

“Now I see parties reverting to the language of a military solution or military option. We must ensure that they do not see that as a solution or an option.”

[Source: Al-Jazeera]