Around 200 families are trapped in a tiny pocket of land in Syria still controlled by Isis and are being bombed by US-led coalition forces, the United Nations has said.

The US-backed Syrian Democratic Forces (SDF) are on the brink of defeating the terror group in its last enclave, which has been reduced to a few dozen tents in a small village in Deir ez-Zor.

The group estimates around 300 Isis militants and about 2,000 civilians are under siege. Michelle Bachelet, the UN’s human rights chief, said militants were stopping some families from fleeing.

Many of the families “continue to be subjected to intensified air and ground-based strikes by the US-led coalition forces and their SDF allies on the ground,” Ms Bachelet said in a statement.

The SDF, who are attacking Isis, has an obligation under international law to take all precautions to protect civilians mixed in with the foreign fighters, her spokesperson, Rupert Colville, told a briefing.

Syria at war: Fleeing the caliphate Show all 14 1 /14 Syria at war: Fleeing the caliphate Syria at war: Fleeing the caliphate Trucks full of women and children arrive from the last Isis-held areas in Deir ez-Zor, Syria Richard Hall/The Independent Syria at war: Fleeing the caliphate Zikia Ibrahim, 28, with her two-year-old son and 8-month-old daughter, after fleeing the Isis caliphate Richard Hall/The Independent Syria at war: Fleeing the caliphate Trucks full of women and children arrive from the last Isis-held areas in Deir ez-Zor, Syria. Richard Hall Richard Hall/The Independent Syria at war: Fleeing the caliphate Men who fled the last Isis-held area of Syria line up to be questioned by American and Kurdish intelligence officials Richard Hall/The Independent Syria at war: Fleeing the caliphate Trucks full of women and children arrive from the last Isis-held areas in Deir ez-Zor, Syria. Richard Hall Richard Hall/The Independent Syria at war: Fleeing the caliphate A young girl pulls her belongings after arriving Richard Hall/The Independent Syria at war: Fleeing the caliphate An SDF fighter hands out bread to women and children after they arrive Richard Hall/The Independent Syria at war: Fleeing the caliphate Sita Ghazzar, 70, after fleeing from the last Isis-held territory in Syria Richard Hall/The Independent Syria at war: Fleeing the caliphate A family from Russia who recently fled the last Isis-held area of Syria Richard Hall/The Independent Syria at war: Fleeing the caliphate Trucks full of women and children arrive from the last Isis-held areas in Deir ez-Zor, Syria. Richard Hall Richard Hall/The Independent Syria at war: Fleeing the caliphate Trucks full of women and children arrive from the last Isis-held areas in Deir ez-Zor, Syria. Richard Hall Richard Hall/The Independent Syria at war: Fleeing the caliphate Trucks full of women and children arrive from the last Isis-held areas in Deir ez-Zor, Syria. Richard Hall Richard Hall/The Independent Syria at war: Fleeing the caliphate Trucks full of women and children arrive from the last Isis-held areas in Deir ez-Zor, Syria. Richard Hall Richard Hall/The Independent Syria at war: Fleeing the caliphate Richard Hall Richard Hall/The Independent

“We understand that [Isis] appears to be preventing some of them if not all of them from leaving. So that’s potentially a war crime on the part of [Isis],” Mr Colville said.

The Isis militants are refusing to surrender and are attempting to negotiate an exit with the forces surrounding them as they hide among civilians in a tiny orchard in the village of Baghouz.

“Civilians continue to be used as pawns by the various parties,” Ms Bachelet said. “I call on them to provide safe passage to those who wish to flee, while those who wish to remain must also be protected as much as possible.

“They should not be sacrificed to ideology on the one hand, or military expediency on the other. If protecting civilian lives means taking a few more days to capture the last fraction of land controlled by [Isis], then so be it.”

The UK-based Syrian Observatory for Human Rights said around 50 trucks had entered the Isis-held area, apparently to bring out some of those trapped inside.

Baghouz: Syrian Democratic Fighters begin final push to recapture the last sliver of territory controlled by ISIS

More than 60 people have died in recent weeks as they fled what remains of Isis territory, the International Rescue Committee said on Monday.

Spokesperson Paul Donohoe said exhaustion and malnutrition are the principal causes of the deaths. He said of the at least 62 people who had died, two-thirds were children under the age of one.

Isis members in the last besieged neighbourhood in the village of Baghouz (Reuters)

More than 30,000 people who left the last Isis-held areas have arrived at the al-Hawl camp in Syria’s northern al-Hasakah province in the past few weeks, raising the overall population of the camp to almost 42,000.

Ms Bachelet also voiced concern for those who had fled the Isis-controlled territories and are being held by Kurdish armed groups, including the SDF, who are reportedly preventing them from leaving the camps, she said.

“Particular care needs to be taken with the civilians, and if possible they should be treated humanely and allowed to leave the camps. They shouldn’t be held in detention unless they are suspected of committing a particular crime,” Mr Colville said.