
Forces loyal to Syrian dictator Bashar al-Assad dropped a barrel bomb on relatives attending a wake for 11 children killed in an earlier barrel bomb in Aleppo.

A helicopter targeted the rebel-held Bab al-Nairab area in the besieged city. As first responders raced to the scene another helicopter dropped a barrel bomb on an ambulance, injuring its driver and delaying the rescue attempts.

At least 15 civilians were killed in today's attack, although it is feared the death toll will rise as rescuers continue to search several collapsed buildings.

15 civilians were killed an dozens were wounded when Syrian Air Force helicopters dropped a barrel bomb on mourners attending a wake in Aleppo for 11 children who were killed in an earlier barrel attack by Bashar al Assad's forces

Rescuers were able to rescue this injured baby from one of the collapsed buildings following this afternoon's attack

Rescuers fear the death toll this afternoon will increase after the string of barrel bomb attacks on Bab al-Nairab

Mohammed Khandakani, a hospital volunteer, said one of those injured told him a barrel bomb was dropped as people paid their respects to 11 children killed on Thursday in an air strike in the same area.

Minutes later, another barrel bomb was dropped, injuring an ambulance driver and hampering rescue efforts.

The Syrian government and its Russian ally are the only ones operating helicopters over Aleppo. The government denies it uses barrel bombs.

On Thursday, 11 children were murdered by the Syrian regime in another barrel bomb attack.

The Syrian Observatory for Human Rights said: 'Fifteen civilians, among them 11 children, were killed in a barrel bomb attack on the Bab al-Nayrab neighbourhood.'

The group also reported eight civilians, including two children, were killed on Thursday in rebel fire on the government-held west of the city.

Bashar Al-Assad's helicopters targeted this ambulance which was racing to the scene of the bombing to assist survivors

Assad's forces regularly target civilian areas with barrel bombs, which are large improvised explosive devices

Assad's forces regularly target rescue workers as they attempt to pull survivors from rubble at the scene of an attack

This girl, pictured, was rescued by a member of the White Helmets who risk death every time they attend a disaster scene

A member of the civil defence White Helmets jumped across the rubble in a bombed out building in Bab al-Nairab, Aleppo

An AFP journalist in Bab al-Nayrab saw rescue workers and civilians digging through the rubble of collapsed buildings.

One man carried out the lifeless body of a baby no bigger than his forearm. Its eyes were closed and its body was white with dust except for speckles and smears of blood.

Nearby, a civil defence worker protected the face of another dead child as his colleagues scraped away the rubble encasing the rest of the child's body.

Syria's regime has been accused of regularly using barrel bombs -- crude, explosive devices -- on rebel-held areas that are home to civilians, and other parties to the conflict are not known to have used the weapons.

President Bashar al-Assad and his government deny using barrel bombs.

Once Syria's economic powerhouse, Aleppo city has been ravaged by the conflict that began with anti-government protests in March 2011.

The city has been roughly divided between rebel control in the east and government control in the west since mid-2012, with each side bombarding the other and causing civilian casualties.

This woman carries a baby as she walks away from the scene of today's latest attack by Syrian government forces

More than 290,000 people have been killed in Syria during the past five years of civil war according to the UN

The United Nations has urged all sides to commit to a 48-hour humanitarian ceasefire to allow aid into Aleppo

The United Nations Syria envoy urged warring parties to state by Sunday whether they will commit to a 48-hour humanitarian ceasefire in the embattled city of Aleppo.

Staffan de Mistura has led global calls for the pause that the UN and aid groups like the Red Cross say is desperately needed by civilians trapped in the midst of brutal fighting between regime and opposition forces.

Russia, which backs Syrian President Bashar al-Assad's forces, has endorsed the plan.

De Mistura said in a statement Saturday that he 'regrets' some opposition camps have expressed reluctance to agree to the plan, without detailing the nature of their concerns.

'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's office said in a statement.

He added that the initial delivery of life-saving aid must be carried out through the strategically crucial Castello Road, which the regime took control of in July, cutting off the last supply route to rebel-held Aleppo.

The UN has 'pre-positioned' aid that is ready to go to the city, it said.

The first delivery would benefit 80,000 people in the rebel-held east as well as people in the government controlled west, the statement said.

'The UN is ready to move,' it added. 'People are suffering and need assistance. Time is of the essence. All must put the civilian population of Aleppo first and exert their influence now.'

An injured girl sits in a vehicle after surviving double airstrikes on the rebel held Bab al-Nairab neighborhood of Aleppo

The UN has 'pre-positioned' aid that is ready to go to the city for the 80,000 people who remain in the east of Aleppo

Civil defence member and men carry a dead body in a damaged site after the double airstrikes. The brutal fight for Aleppo intensified two months ago

According to de Mistura, Russia 'has engaged' its ally Assad on the plan.

The brutal fight for Aleppo, Syria's second city, intensified two months ago.

After a nearly three-week siege by regime troops, rebels early this month linked up with opposition-held neighbourhoods via a new road from the city's south, in a major blow to forces loyal to Assad.

But fighting has continued near the new supply line, which recently has been bombarded almost daily, affecting supplies coming into the city's opposition-controlled neighbourhoods.

Around 250,000 people live in the city's eastern districts, while another 1.2 million live in its western neighbourhoods.

More than 290,000 people have been killed in Syria since the conflict began more than five years ago.

Syrian people help emergency services as they try to fight survivors in the wreckage after the blasts in Aleppo