But government forces ramped up military pressure on Eastern Ghouta starting Sunday, sending more than 260 rockets sailing onto opposition-controlled towns there.
In the East Ghouta town of Hamouriya alone, airstrikes on "residential areas" killed at least 20 people throughout Monday, the Civil Defense reported. Although the operation may allow Assad to exterminate the jihadists from Eastern Ghouta, it will also result into unprecedented civilian casualties, said Observatory head Rami Abdel Rahman.
An onslaught by the Syrian government and its allies has killed about 200 civilians since Sunday in the suburbs of the country's capital, Damascus, according to a United Kingdom -based monitoring group and a consortium of aid groups.
The Arab League chief added that the situation would lead to the fall of many civilian victims, calling for stopping the attack on humanitarian grounds, added the spokesman.
The statement said unhindered humanitarian access to civilians inside Syria and the protection of civilians and infrastructure was a matter of urgency to prevent further loss of life.
Ghouta has not seen a single humanitarian aid convoy for two months.
Identifying himself as Abu al-Yasar, he described treating a one-year-old brought into the Arbin hospital with blue skin and a faint pulse, rescued from under the rubble. "It seems that there's no solution but a full-blown military one", he told AFP.
The targeted suburbs have been subjected to weeks-long bombardment that has killed and wounded hundreds of people. Food, medicine, and other basic necessities are almost impossible to obtain.
Smoke mushrooms skyward amid the bombardment Monday on rebel-held Eastern Ghouta. At least one person died from rebel mortar fire in the capital on Monday.
He said negotiations were taking place, with Russian involvement, for the evacuation of jihadist fighters whose footprint in Ghouta is limited but includes areas directly adjacent to Damascus.
But the escalating bombardment suggests the regime will likely opt for a ground assault.
It has since evolved into a war that has carved up the country into rival zones of control among the regime, rebels, jihadists and Kurdish forces.
Ankara considers the YPG a "terrorist group" linked to the Kurdish insurgency within Turkey's borders.