The U.K. on Thursday asked the UN Human Rights Council to hold an "urgent debate" this week on the situation in Syria's besieged Eastern Ghouta.
"I am writing to formally request that the Human Rights Council convene an urgent debate on the situation in Eastern Ghouta in the Syrian Arab Republic," Julian Braithwaite, Britain's ambassador and permanent representative to the UN at Geneva, said in his letter to the Council.
Noting "the extremely serious deterioration" in the human rights situation in Eastern Ghouta, Braithwaite said: "I request that the session be held this week. In convening this urgent debate, we will call upon the Council to adopt a resolution, which we will circulate as soon as possible."
The UN said in a statement it is considering the request.
"The Bureau of the Human Rights Council will consider and discuss the matter today," it said.
Also on Thursday, a UN adviser urged Russia and the U.S. to help in the delivery of aid and civilian and medical evacuation from Eastern Ghouta, after the regime refused permits to aid convoys.
Speaking at a news conference, Jan Egeland, adviser to the UN special envoy for Syria, said: "So far, we have not been able to move any convoys to Eastern Ghouta apart from one little convoy in mid-February. It is because we have not gotten a single facilitation letter by the Syrian government."
Last Saturday, the UN Security Council adopted a resolution calling for a 30-day cease-fire in Syria without delay.
Eastern Ghouta, a Damascus suburb, has been under siege for the last five years and humanitarian access to the area, which is home to some 400,000 people, has been completely cut off.
In the past eight months, forces of the Assad regime have intensified their siege of Eastern Ghouta, making it nearly impossible for food or medicine to get into the district and leaving thousands of patients in need of treatment.
Hundreds have been killed by the Assad regime airstrikes in recent days.
"We will call again Russia, U.S. and these countries, who have influence in Eastern Ghouta and other places, to beg them to help us with several things: get several convoys per week to reach all of Eastern Ghouta, get 1,000 priority medical cases evacuated from Eastern Ghouta and also to see evacuation of civilians out of the conflict zones," Egeland said.
"All of this should be possible if the UN Security Council resolution becomes a reality. Since the resolution was adopted, it did not get better, it has gotten worse," he added.
Egeland also said a Russian plan for a five-hour pause in the fighting in Eastern Ghouta "is not enough".
"We need much more than five hours," he added.
Syria has been locked in a devastating conflict since early 2011 when the regime cracked down on demonstrators with unexpected ferocity.
According to UN officials, hundreds of thousands of people have been killed in the conflict to date.