As many as 12,000 people have fled fresh fighting between Sudan's army and Darfur rebels and are heading towards already overcrowded camps and settlements in the strife-torn territory, peacekeepers said on Sunday.

Sudan's army has clashed with insurgents in the South Darfur village of Khor Abeche at least three times this month, drawing sharp criticism from UN envoys.

"The Mission has noticed that approximately 12,000 people fled the area and are moving towards Shangil Tobaya and Zam Zam internally displaced persons camp, near El Fasher, North Darfur," said Darfur's UNAMID peacekeepers in a statement.

Sudan's army attacked fighters from the Sudan Liberation Movement loyal to Minni Arcua Minnawi last week and fighting continued on Friday, said the joint UN/African Union peacekeeping force.

Minnawi was the only rebel leader to sign a 2006 peace deal with the government. Sudan's army declared Minnawi a military target earlier this month, accusing him of breaking a ceasefire and plotting to join rebels still fighting the government.

The fighting was the final nail in the coffin for the troubled peace deal, which was boycotted by the region's two main rebel groups and did nothing to halt the spread of lawlessness, banditry and violence in the territory.

UNAMID said 100 people had already arrived in North Darfur by Saturday.

Aid agencies had started sending in medical kits and other supplies, said the UN Office for the Coordination of Humanitarian Affairs in a statement.