At least 417 civilians have died and more than 2,100 have been injured in airstrikes in eastern Ghouta, in the outskirts of Damascus in Syria, since Sunday, the Syrian Observatory for Human Rights said on Thursday. The monitor said President Bashar al-Assad’s regime had launched more than 340 shells and missiles in two hours in the besieged region on Thursday, and that dozens were still missing, trapped under rubble.

The airstrikes by Syria’s military and allies, including Russia, targeted several hospitals and residential areas where four lakh people lived, medical charities said, adding that the assault had made it impossible to tend to the wounded. Aid workers and residents said helicopters of the Syrian Army had been dropping “barrel bombs” – oil drums packed with explosives and shrapnel – on markets and medical centers, Reuters reported.

Even as the airstrikes continued to wreak havoc in the last rebel-held region in Syria, Russia blocked a United Nations resolution in the Security Council, which would have brought about a month-long ceasefire across the war-torn country to allow medical evacuations and delivery of emergency aid, The Guardian reported.

Russia had called for the emergency meeting to discuss what is being considered the most vicious string of airstrikes in the seven years of the civil war. Russian envoy to the UN Vassily Nebenzia rejected the resolution framed by Sweden and Kuwait, calling it unrealistic in its current form.