Since the so-called Islamic State laid siege to the devastated Palestinian refugee camp just outside Damascus, 27-year-old Ahmad, the renowned piano player of Yarmouk, can no longer roll his treasured piano on his uncle's vegetable cart and play music in the grim laneways.

Under threat from the extremist group that for now controls much of the camp, he is less mobile but far from silent, as his friend, co-composer and Yarmouk exile Abo Gabi, told Fairfax Media.

A Palestinian-Syrian musician and filmmaker, 31-year-old Abo Gabi fled Yarmouk in May 2013, six months after the clashes between Syrian regime forces and the Palestinian militant group PFLP-GC on one side and Syrian rebels on the other marked the moment the camp became one of the most vicious epicentres of Syria's four-year civil war.

"For us, it became a milestone when in December 2012 the camp was hit by air strikes," Abo Gabi says. "People started to say . . . before the MiG [fighter jet] and after the MiG."

Since then the situation inside the camp - established in 1957 and once home to 180,000 Palestinian refugees and their families who were forced to flee from what is now Israel - has moved beyond desperate, he says.

"In Aleppo there have been barrel bombs and mortars being thrown over the people but they can still eat. In Yarmouk, people are dying of starvation and the UN is unable to convince the regime to send in food for people," Abo Gabi says.

"Meanwhile, only 50 metres from the entrance to the camp people are living a normal life - they have supermarkets, bakeries, they go to the mosque . . . so the tragedy is increasing, everyone is waiting for the death of another, sons are watching their elderly fathers die, nobody knows who will die first."

IS militants overran much of Yarmouk early this month, giving the group its first stronghold close to Damascus, just over six kilometres away. The renewed fighting has pushed more of the area's remaining 16,000 residents - including 3500 children who have already endured a two-year siege and ongoing bombardment from Syrian regime forces - close to starvation and death, the United Nations has warned.

An activist from inside Yarmouk who asked not to be identified for fear of reprisals from all the warring factions told Fairfax Media via text message that rumours IS had agreed to leave the camp were premature. He says there were renewed clashes in the south of the camp between the Palestinian Aknaf Beit al-Maqdis militia and IS fighters, backed by militia from the al-Qaeda-linked Nusra Front.

Salim Salameh, head of the Palestinian League for Human Rights Syria and a former Yarmouk resident, says many inside the camp are back to consuming water with spices, "the famous meal people had during 2014 when starvation took the lives of around 200 people".

"This news is extremely scary because it means the basic food storage which people had accumulated in the 2½-year siege is already exhausted," Mr Salameh, who is now based in Sweden, told Fairfax Media.

Along with the threat of starvation, the Syrian regime forces dropped two barrel bombs on the one remaining hospital that is still operating inside Yarmouk on April 9, further eroding what's left of the healthcare infrastructure of the camp. There are just 42 medical workers - two of them doctors - left in the camp with next to no medication for pre- or post-emergency treatment, he warned.

On Monday, the United Nations Relief and Works Agency (UNRWA) announced it had distributed humanitarian assistance to 500 civilians in the nearby neighbourhood of Yalda, to which many of Yarmouk's residents have fled. However the security situation remains so dangerous that UNRWA remains unable to enter the camp and provide aid to those most in need.

Ayham al-Ahmad and Abo Gabi remain separated by the siege - a situation beautifully and painfully illustrated in Abo Gabi's short film  Blue, set on the grim streets of Yarmouk and featuring the pianist's pointed, political compositions.

In the film, young men gather around his piano, Ahmad at the keys, and they sing with gusto: "What is with these days, the world sends delegations, delegates come and go, delegations multiply and so do their promises, while our people die."

"I think about nothing but music," Ahmad says in Blue. "The future is a nasty question." Then there is the sound of mortars and the group quickly moves the battered piano to a safer location.

Fairfax Media was unable to contact Ahmad for this story - Abo Gabi says it is increasingly difficult to connect with people in the camp, such is the chaos that surrounds them.

"Now we are composing a song together over the internet, I am writing the lyrics for Ayham and he will compose the music," Abo Gabi says.

With friends in Yarmouk, he became involved with the Palestinian Assembly of Creativity, so young people in the camp could come together and explore their creativity despite the suffering, he says. "We started with stand-up comedy during the war, we used to focus on social issues and later on when the siege began on the camp, the focus turned towards politics and speaking about the revolution."

These days most of those involved in the Assembly have fled and are scattered around the world, and the two artistic collaborators struggle to connect between Paris and Damascus via what little internet service there is left in Yarmouk.

"As a refugee, the film [Blue] reflects the suffering of the people, the way they are having to live there in Yarmouk, where there is nothing except death for them," Abo Gabi says. "I am showing the presence of death along with the presence of the living."