Around 277 civilians including dozens of children were killed and more than 812 injured in the period between February 4 to 9, as the Assad regime intensified bombardment at the besieged Eastern Ghouta outside Damascus and the city of Idlib.

This comes in a statement released by the UN High Commissioner for Human Rights Zeid Ra’ad Al Hussein on Saturday calling for an urgent international action after a week of soaring violence and bloodshed.

The statement described the last week as one of the “bloodiest periods of the entire conflict with wave after wave of deadly airstrikes leading to civilian casualties in areas of Eastern Ghouta and Idlib”. Nine medical facilities, six of them in Idlib and three in Eastern Ghouta, were hit by airstrikes.

“My staff in the region have catalogued dozens of specific incidents that have reportedly led to deaths, injuries and destruction of vital infrastructure over the past week,” Zeid said. “These range from a rolling series of airstrikes on residential areas of Duma on February 6 which reportedly killed at least 31 civilians, including 12 women and four children, and injured more than 100 others, including 37 children.”

Air strikes damaged at least nine separate medical facilities ranging from a key hospital that was still functioning in Idlib to a mental health care facility and a medical clinic in Kafr Batna in Eastern Ghouta, the statement read.

The UN Human Rights Office staff have received reports, including video footage, suggesting that toxic agents may have been released on February 4 following airstrikes on a residential area of eastern Saraqib city, although there were no reported deaths during this attack.

On the other hand, the statement said that several rockets and mortars were fired from opposition-held areas into populated areas of government-held Damascus and surrounding suburbs, reportedly killing at least seven civilians and 18 others were injured between February 6 to 9.

The conflict in Syria has killed more than 340,000 people since 2011, that started when people went to the streets in peaceful protests against strongman President Bashar Al Assad and his government regime. In Eastern Ghouta alone, an estimated 400,000 inhabitants are suffering severe shortages of food and medicine since 2013. The UN said earlier that at least 500 people are in a critical condition inside the neighbourhood and in urgent need to be evacuated for medical treatment.