DAMASCUS (AFP) - Arriving at the rubble of the Palestinian Yarmuk refugee camp in Damascus, Ms Hadia al-Fut discovered that her husband had been killed while fighting in the ranks of a pro-regime Palestinian group.

Worse still, she found there was little chance she would be able to recover his remains because the rebels who killed him in an ambush a day earlier were holding out for an exchange for bodies.

Ms Hadia, a Palestinian, had fled Yarmuk because of ongoing fighting there, but was back at the camp to meet her husband.

"We had an appointment because we had to register our 19-month-old son," she said between sobs.

"When I arrived, I was told that he and his whole group were killed in an ambush by Al-Nusra Front," she added, referring to a jihadist rebel group.

Her husband Mohamed had been fighting in the ranks of the Popular Front for the Liberation of Palestine-General Command (PFLP-GC), a pro-regime Palestinian group led by Ahmed Jibril.

Just 27, he was a taxi driver before the war, and decided to join the PFLP-GC a year ago despite being Syrian.

"I want to see my husband one last time. I want to know where he was buried," Ms Hadia said tearfully.

But the possibility of retrieving his body seemed slight because the rebels who killed him were holding out for an exchange for bodies.

She discussed it with with a PFLP-GC leader, as the sounds of battle - gun and automatic weapons fire - continued around them.

"I need to have him close to me, but there's no hope, because his friends don't have a body to exchange for his," she said, holding the hands of her son and seven-year-old daughter Sira.

In an apartment in part of the camp controlled by the faction, the smell of death hovered over a body wrapped in sheets.

The Palestinian pro-regime fighters said it was that of a foreign rebel, but opposition forces refused to accept it in an exchange because the corpse couldn't be identified.

Yarmuk has been the scene of fierce clashes for months between opposition fighters and forces loyal the regime of President Bashar al-Assad.

The area was established in 1957 as a camp for Palestinian refugees, but has gradually become a district of the capital.

It is home to around 450,000 people, including 150,000 Syrians, and many mixed marriages like that of Ms Hadia and Mr Mohamed.

The 500,000 Palestinians in Syria stayed largely outside of the conflict between the opposition and regime for its first 18 months.

But from December 2012 onwards, they have been increasingly involved, despite calls from the regime and international organisations for them to remain neutral.

"Today, we control 25 percent of the camp after offensive that was launched a month ago. I'm sure that with time we will retake it completely," said Mr Jumaa al-Abdallah, the PFLP-GC's chief in Yarmuk.

The assessment is rather optimistic.

The group, which is allied with other pro-regime Palestinian factions including Fatah al-Intifada, the Abu Nidal Front, the Palestine Liberation Front and al-Saiqa, has in fact advanced just 200 metres inside Yarmuk.

The pro-regime forces say they are facing an alliance of more than 2,000 fighters from Hamas, the Al-Nusra Front, the Ibn Taymiya Brigades and the Fatah movement of Palestinian president Mahmud Abbas.

For Yarmuk residents caught in the middle, life is miserable.

The part of the camp retaken by the pro-regime forces is deserted, and the some 50,000 mostly Palestinian residents of areas controlled by the rebels have almost no access to food because exits are blocked by rubble or off-limits because of snipers.

"There's no more bread, no milk, we're eating crushed rice, lentils and burghul," said resident Abu Rashid, who has lost 6kg in two months.

"I'm strong and I've become a skeleton, and my four children have yellow faces. There is no electricity, only water. I stay because I have no place to go," the 60-year-old said.

The Syrian army is not involved in the fighting at Yarmuk, and at Batiha Square, just a single police station remains open.

"Nine months ago, the rebels attacked. We were surrounded for 48 hours and out of 25 of us, four were killed and five were injured," said Mr Abu Jaafar, a police officer.

"Today, things are better, but as you can imagine, no one comes to report anything to us or ask for our help."