A helicopter contracted to UN-led peacekeepers crashed in Sudan's Darfur region on Monday, killing two people with two more feared dead, a UN spokesperson said.

A spokesperson for the joint African Union-United Nations peacekeeping mission in Darfur (UNAMID) said the helicopter was contracted to carry food to a force team site in South Darfur state.

"Two of the crew on board the helicopter were killed, and two more are missing in the wreckage," said UNAMID spokesperson Kemal Saiki.

The helicopter, carrying two tons of supplies, crashed shortly after take-off at around 9.20am from Nyala airport, the state capital of South Darfur.

The force is investigating reports the helicopter was fired at. The helicopter is privately owned by a Sudanese company but is painted white as is usual for UN aircraft.

"There are rumours that the helicopter was shot at, but we can neither confirm nor deny this at present," added Saiki.

"We are investigating now, and we have also sent a rescue team to the site."

The helicopter is reported to have crashed close to Kalma camp, a sprawling hut-city outside Nyala for internally displaced people.