Barrel bomb 'double tap' kills at least 15 funeral mourners in Syria's Aleppo

At least 15 funeral mourners were killed in a barrel bomb attack on a rebel-held district of Syria's Aleppo on Saturday, as the UN envoy for Syria called for all warring sides to agree by Sunday to allow the first safe delivery of relief supplies to the divided city.

The Britain-based group Syrian Observatory for Human Rights monitor said government aircraft dropped two explosive-packed barrel bombs several minutes apart on the Maadi district of eastern Aleppo.

Syrian civil defence, a volunteer rescue group, told Al Jazeera that Syrian government aircraft hit a group of people gathered in the al-Maadi neighbourhood to mourn the deaths of 15 women and children killed in a raid earlier this week. 

The strikes hit "near a tent where people were receiving condolences for those killed this week in the neighbouring district of Bab al-Nayrab," Observatory director Rami Abdel Rahman said.

"There was a first barrel bomb, and when people gathered and the ambulances arrived, a second barrel struck and there were more deaths," an AFP reporter in the rebel-held part of the city said.

"One ambulance was completely destroyed," he added, citing the local civil defence unit.

The Observatory said dozens more were wounded in the two strikes and the death toll was expected to rise.

Sam Kiley of Sky News, in Gaziantep, Turkey, said this kind of assault is known as the "double tap" in Aleppo.

Luring rescue workers to scenes of carnage caused by barrel bombs and then dropping a second on them, he said, has become a standard tactic of the government.

The local Shabha Press news agency said 23 people were killed in Saturday's attack, and published photos showing several of the dead, including a man who appeared to have been riding a motorbike at the time of the strike.

Most of his bloodsoaked body lay on one side of the overturned bike, but his severed leg lay on the other side.

UN calls for 48-hour pause in fighting

The United Nations Special Envoy for Syria called for all warring sides to agree by Sunday to allow the first safe delivery of relief supplies to Aleppo.

The U.N. is seeking a weekly 48-hour humanitarian pause to deliver food, medicines and other aid to people in rebel-held eastern Aleppo as well as those in the government-controlled western part of Syria's second city. It also wants to repair the electricity system to deliver power and clean water supplies to 1.8 million people, amid fears of disease outbreaks.

Staffan de Mistura said in a statement on Saturday that for logistical and operational reasons convoys must go via the Castello Road during the first pause, although he was aware of rebel opposition to using that government-controlled route.

"The Special Envoy calls for all concerned to exert every effort so that, by this Sunday, 28 August 2016, we know where we stand," de Mistura said. There should be "no (military) escalation in areas adjacent or around the area of the pause".

Russia, the main ally of the government of Bashar al-Assad, has already accepted the UN plan, saying it is ready to ensure compliance, while the United States and other states are working to get other parties to commit, de Mistura said.

U.N. agencies have said that supplies including surgical material for treating war wounds and even baby milk have been removed from U.N. convoys at government checkpoints throughout the five-year conflict.

The main alliance of rebel groups in Aleppo, in a statement, gave conditional approval to use of Castello road but said the "shortest and fastest" Ramouseh road south of Aleppo should be used in parallel to deliver supplies to eastern Aleppo.