Syrian regime air strikes killed at least 33 people, mainly women and children, on Thursday in the worst ceasefire violation yet in a key opposition-held bastion east of the capital Damascus, a monitoring group said.
Dozens more were wounded in the raids on Deir al Assafir, a town in the opposition stronghold of Eastern Ghouta, according to the Syrian Observatory for Human Rights.
The strikes, which killed 12 children, nine women, two police officers and ten other victims represented "the largest ceasefire violation in Eastern Ghouta," head of the SOHR Rami Abdel Rahman said.
A rescue organisation volunteer worker, Walid Ghourani, from the "White Helmet" organisation was killed when one of its ambulances was hit in the attack.
Videos of the blast spread over social media showing civilians rushing to help women and children stuck under large blocks of concrete and debris.
— _tintin_ (@1957_Tintin_) March 31, 2016
A similar video was recorded by a group of White Helmet workers who were almost hit by rocket fire while in a car heading towards the targeted civilian areas.
— Sakir Khader (@sakirkhader) March 30, 2016
A fragile ceasefire brokered by the United States and Russia has been in place across parts of Syria, including Eastern Ghouta, since February 27.
The truce does not include areas where DAESH and Al Qaeda's local affiliate Nusra Front are present.
Eastern Ghouta is dominated by a powerful rebel group, which has agreed to the truce, but there are also small pockets of Nusra Front rebels.
Amateur footage filmed by activists and distributed online showed a man holding up the lifeless body of an infant wrapped in a white shroud.
"Are these fighters? They are children!" the man says in the video.
The Istanbul-based National Coalition opposition group condemned "the massacre carried out by regime forces against residents of Deir al Assafir."
In a statement, it called on the international community to take "serious, urgent measures" to address the latest violation.
Although there have been occasional incidences of violence, some of them deadly, the ceasefire has controversially been hailed as a success by the United Nations.
The UN estimates the death toll in Syria, since the start of the war in 2011 to be at least 250,000. But the Syrian Centre for Policy Research released a report on February 10 stating that the death toll has now exceeded 470,000.
Around 5 million Syrians have been taken refugee in the neighbouring countries of Turkey, Lebanon, Iraq and Egypt as Turkey has the highest amount with almost 3 million.