The government troops -- backed by helicopters, Antonov ASTC planes and militias on horseback and camel -- attacked insurgent bases in Disa, about 90 miles northwest of the North Darfur capital Al-Fashir, and Birmaza, a few miles north of Disa, leaders of three rebel groups said.

Two insurgent groups said Sudanese troops also attacked settlements near Tawila, 45 miles southwest of Al-Fashir.

The insurgents said the government and militias sought to loot, if not destroy, the towns to secure control of the territory and gain access to key transportation routes for oil reserves.

The Sudanese military had no immediate comment on the rebel claims, the BBC reported.

The joint United Nations-African Union Mission in Sudan said it was investigating.

Rebels accused the government in July and August of starting a massive attack to flush them out from stronghold positions.