
This is the horrifying scene left behind after Syrian regime forces reportedly bombed a bunker in eastern Ghouta with Napalm overnight, burning at least 37 civilians to death.

Images circulated online by the Syrian Civil Defence, a rescue group otherwise known as the White Helmets, showed volunteers pulling charred bodies from the ruined shelter.

Rebel group Failaq al-Rahman, which controls the town of Arbin, said around 125 people, mostly women and children, were inside the shelter when the bomb exploded just before midnight when a ceasefire was supposed to take effect.

Sources on the ground and rescuers from the Syrian Civil Defence claimed the air strikes were carrying napalm gas.

At least 37 people were burned to death after an underground shelter in the town of Abrin, in Eastern Ghouta, was reportedly hit with 'Naplam' by regime forces overnight, according to observer groups and witnesses

Failaq al-Rahman, the rebel group in control of Arbin, said around 125 people - mostly women and children - were in the shelter at the time the bomb struck, and they expect the death toll to rise. Above is an image being circulated on social media, purporting to show the scene in the bunker after the attack

Syrian government forces also dropped bombs containing what appeared to be white phosphorus, a banned weapon, over the rebel-held town of Douma overnight on Thursday

Douma, which is controlled by the Jaish al-Islam group, is one of just two rebel enclaves left in the Eastern Ghouta region. A third, around the town of Harasta, was emptied of fighters overnight

The night sky in Douma was illuminated with dozens of fires overnight as incendiary bombs were dropped on the city in an attempt to retake it from the rebels

A man tries to extinguish flames after a building was set alight in Douma overnight. It is unclear if there were any casualties in the raids, which happened in the early hours of Friday

Izzet Muslimani, an activist in the town, told Al Jazeera: 'Those who were injured are still being treated for first and second degree burns. With the lack of emergency services, we are expecting the death toll to rise.'

There were conflicting reports over who was responsible. The Britain-based Syrian Observatory for Human Rights attributed the attack to Russia.

Activists on the ground said the Syrian air force was responsible for the atrocity. The use of Napalm in warfare is effectively banned under international weapons treaties.

Moscow denied Friday it was bombing Eastern Ghouta with incendiary weapons after war monitors said Russian air strikes killed the 37 civilians.

'Russian aviation is not striking residential areas of Eastern Ghouta and especially it is not using incendiary weapons, unlike the US-led international coalition,' the Russian defence ministry said in a statement, quoted by TASS state news agency.

Rebels in Arbin had earlier said they were hoping to be allowed to evacuate the city under a ceasefire, the term of which had been provisionally agreed, though it never materialised. Negotiations were continuing on Friday.

Elsewhere rebels were allowed to evacuate the town of Harasta, with up to 400 fighters and their families taken out of the enclave on government buses bound for Idlib province.

This follows a pattern which the Syrian government and its Russian allies have used elsewhere in the conflict: lay siege to an area, bombard it, launch a ground assault and finally offer passage out to rebels who agree to leave.

A man watches helplessly as a building is consumed by fire following airstrikes using what appeared to be white phosphorous bombs in Eastern Ghouta

Ghouta has been under siege for the best part of five years but attacks on the region drastically escalated in February as the government pushed to retake the region (pictured, a fire burns in Douma)

The Syrian government and its Russian allies are using a tactic they have repeated throughout the war to recapture Ghouta - lay siege, bombard, send in ground troops, then offer evacuation to any rebels left (pictured, fires burn in Douma)

Bashar al-Assad and Russia have been accused of indiscriminately using weapons against both civilians and rebels which has seen some 1,500 innocents killed in Ghouta in the last month, according to observer groups

A man attempts to extinguish fires inside a building using nothing more than a bowl filled with water on Friday in Douma

Up to 400 rebel fighters and their families were allowed to flee the town of Harasta overnight on government buses, effectively bringing the rebel stronghold under Assad's control

Meanwhile in a third and final rebel enclave in the town of Douma, bombs containing what appeared to be white phosphorous, another banned weapon, rained down on the city overnight.

Videos and pictures from the ground showed dozens of fires burning around the city in hellish scenes.

If the evacuation of Arbin is successful, that would leave only the town of Douma still under rebel control.

Pro-regime forces launched a blistering air and ground offensive on the Eastern Ghouta region on February 18.

The assault has retaken 80 per cent of the enclave, the Syrian Observatory For Human Rights says, and what remains is within mortar range of Damscus, allowing for constant bombardment.

The one-month offensive on Eastern Ghouta has killed more than 1,500 civilians, the Observatory says, and caused tens of thousands to flee into government-held areas.

More than 350,000 people have been killed in the Syrian conflict since it broke out in 2011 with the brutal repression of anti-government protests.