The situation in the Yarmouk Palestinian refugee camp in Damascus is spiralling out of control as desperate UN officials seek access to the area, which has seen assaults from Islamic State (Isis) militants.

The latest deterioration has put the lives of 18,000 people in conditions "beyond inhumane" according to a UN official.

No aid has reached the residents in the area since violence began last week. Clashes broke out after some 300 IS militants stormed the area alarming the Syrian rebels, who are already fighting forces loyal to President Bashar al-Assad.

The anti-Assad groups, spearheaded by Palestinian militia and fighters belonging to the Free Syrian Army, are currently confronting the IS Sunni extremists, who have made concerted efforts to consolidate their hold since 1 April. Yarmouk is the largest Palestinian refugee camp in Syria.

The increasing violence has forced the 15-member UN Security Council to hold an emergency session.

The United Nations Relief and Works Agency (UNRWA) said: "Never has the hour been more desperate in the Palestine refugee camp of Yarmouk. We demand humanitarian access and the establishment of secure conditions under which we can deliver life-saving humanitarian assistance and that enable civilians to be evacuated."

A delegation is said to be on its way to Syria to hold discussions with the government in Damascus to resolve the crisis.

Describing the dire conditions at the refugee camp, Chris Gunnes, an official with the UNRWA, said: "The situation in the camp is beyond inhumane. There is no food, there is no water and there is very little medicine... People are holed up in their houses, there is fighting going on in the streets. There are reports of... bombardments. This has to stop and civilians must be evacuated."

Briefing the UNSC via a video-conference, Pierre Krahenbuhl, the chief of the UN agency for Palestinian refugees, said the circumstances are "more desperate than ever".

IS is not known to have a significant presence in Damascus suburbs, but its latest offensive is bound to pose serious challenges and spark fresh violence in the war-torn region.