Sudanese rebels say they shot down an army helicopter and killed 26 government soldiers in fighting in Sudan's southern Blue Nile state.

A spokesman from the Sudan People's Liberation Movement-North says the clashes took place earlier this week near the state capital of Ed Damazin.

Army officials deny the rebels shot down one of their helicopters. They say soldiers killed seven rebels and that six government troops were wounded.

Fighting broke out in September between Sudanese forces and SPLM North rebels, who sided with the now independent south during Sudan's decades-long civil war.

The United Nations says the fighting has driven about 500,000 people from their homes.