KHARTOUM, Sept 30, 2008 (AFP) - Rebels in Sudan's war-torn Darfur region on Tuesday rejected claims they had shot down a helicopter contracted to the UN-peacekeeping force in an incident that killed all four crew members.

Sudanese police have accused Darfur rebels of bringing down the helicopter, which crashed on Monday close to Kalma camp, a sprawling hut-city for internally displaced people which Khartoum says is an insurgent stronghold.

But rebels from the Sudan Liberation Army (SLA) dismissed the accusations, saying the estimated 80,000 camp residents were civilians, not fighters.

'This crime was a terrorist act that we had nothing to do with,' said Mahgoub Hussein, a London-based spokesman for the SLA-Unity faction.

'We condemn this act, and deny involvement.'

SLA-Unity is one of the rebel groups with the most supporters in Kalma camp. Other groups were not immediately contactable.

The helicopter was privately owned by a Sudanese company but was contracted by the joint African Union-United Nations peacekeeping mission in Darfur (UNAMID) and was painted white, as is usual for UN aircraft.

It crashed shortly after takeoff from the South Darfur state capital Nyala on a flight to deliver two tonnes of supplies.

UNAMID spokesman Kemal Saiki said on Monday it was investigating the incident but could not confirm or deny rumours the helicopter was shot down.

Earlier this month the European Union condemned the Sudanese military's use of white aircraft in Darfur, calling it a deliberate attempt to create confusion with UN planes. Sudan rejected the claims.