BEIRUT // Shelling and sporadic clashes struck a Palestinian refugee camp under attack by extremists in the Syrian capital on Monday, a situation that a UN official described as “beyond inhumane.”

Hatem Al Dimashqi, an activist based in an area just south of Damascus, said the Yarmouk camp was under attack on Monday. Both Mr Al Dimashqi and the Britain-based Syrian Observatory for Human Rights also said Syrian government’s air force has dropped several barrel bombs on the camp since Sunday.

ISIL militants stormed the camp on Wednesday, marking the extremist group’s deepest foray yet into Damascus. Palestinian officials and Syrian activists said they were working with rivals from the Al Qaeda affiliate in Syria, Al Nusra Front. The two groups have fought bloody battles against each other in other parts of Syria, but appear to be co-operating in the attack on Yarmouk.

Al Nusra said in a statement it is taking a neutral stance in the camp.

Chris Gunness, a spokesman for the UN agency that supports Palestinian refugees known as UNRWA, said late Sunday that the agency has not been able to send any food nor any convoys into the camp since the fighting started.

“That means that there is no food, there is no water and there is very little medicine,” he said. “The situation in the camp is beyond inhumane. 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.”

He said 93 people have been evacuated from the camp so far.

The United Nations says around 18,000 civilians, including a large number of children, are trapped in Yarmouk. The camp has been under government siege for nearly two years, leading to starvation and illnesses. The camp also has witnessed several rounds of ferocious and deadly fighting between government forces and militants.

Mr Gunness said the camp has been under siege for nearly two years, adding that “things were bad and things got worse when the fighting engulfed the camp.”

Meanwhile, talks on ending the war in Syria were set to start in Moscow on Monday but the absence of key opposition groups meant there was little hope of progress in resolving the conflict.

Also on Monday, militant fighters kidnapped some 300 Kurdish civilians at a checkpoint in northwestern Syria, Kurdish officials said. It was not immediately clear which group was responsible for the kidnapping, but Kurdish officials accused Jabhat Al Nusra, which is active in Idlib province.

* Associated Press, Agence France-Presse