Syrian government forces kill dozens after UN ceasefire adopted, watchdog says

Russia said it will establish a five-hour daily truce starting Tuesday.

A resident of Douma, who asked that her real name be withheld for security concerns, said she was hiding from the bombardment in her living room, away from the doors and windows.

"Warplanes and helicopters are dropping rockets and artillery shells are being fired, as well," she told ABC News.

In the past week, the Syrian government and its allies have intensified attacks on Eastern Ghouta, killing at least 561 civilians, including 139 children, according to the Syrian Observatory for Human Rights.

On Sunday, the White Helmets said that warplanes dropped missiles containing chlorine on the town of Shayfuniya in Eastern Ghouta.

Doctors said they treated several victims with symptoms consistent with exposure to chlorine -- and that one child choked to death. The Syrian Observatory for Human Rights corroborated the account that several people in the area had signs of choking and one child died.

On Monday, the head of the U.N. called for the ceasefire to be implemented immediately, to ensure the delivery of humanitarian aid and the evacuation of the sick and wounded.

The recent surge in violence in Eastern Ghouta, which has been besieged by the Syrian government since 2013, is part of president Bashar al-Assad’s campaign to seize Syria’s last remaining opposition-held territories. The Syrian government and Russia say their military offensive against Eastern Ghouta is necessary to overthrow rebels who have been firing mortars on Damascus.