Gulf states Saudi Arabia and the United Arab Emirates called Thursday on Damascus to "stop the violence" in its deadly assault on the rebel-held enclave of Eastern Ghouta.
"We stress the need for the Syrian regime to stop the violence, to allow in humanitarian aid, and to take seriously the path of a political solution to the crisis," the Saudi foreign ministry said on Twitter.
"We are concerned over the continuation of Syrian regime attacks on Eastern Ghouta and the impact on civilians there," it added, stopping short of an outright condemnation.
It urged Damascus to adhere to UN Security Council resolution 2254, which calls for a nationwide ceasefire and a political transition.
The Emirati foreign ministry expressed concern at the escalation of violence and called for an "immediate truce" to halt the bloodshed and protect civilians. It also called for allowing humanitarian and medical aid to civilians.
Gulf states, mainly Saudi Arabia, have been key backers of Syrian opposition groups fighting President Bashar al-Assad and Riyadh has hosted meetings of the opposition.
In recent months Riyadh and Abu Dhabi have softened calls for ousting Assad, instead urging a political settlement to the seven-year conflict.
Syrian jets have been raining bombs on the eastern suburbs of Damascus in recent days, killing more than 300 people and prompting an international outcry.
United Nations chief Antonio Guterres described the death and devastation that has engulfed Eastern Ghouta since Sunday as "hell on earth", and joined France in calling for an immediate humanitarian truce.
The UN Security Council is expected to vote, probably on Thursday, on a draft resolution demanding a 30-day ceasefire to allow deliveries of aid and medical evacuations.
Syria's complex, multi-sided seven-year war has claimed more than 340,000 lives, forced millions to flee their homes and left entire cities in ruins.
© 2018 AFP