Rebels in Sudan's Darfur region have launched an attack on government troops, with both sides claiming to have inflicted heavy casualties.

The Justice and Equality Movement (JEM), part of a rebel alliance that wants to topple the government in Khartoum, said it attacked an army camp in Wad Ganja, east of the state capital El Fasher on Saturday, killing several soldiers, destroying 15 army vehicles and taking several prisoners.

Army spokesman al-Sawarmi Khalid confirmed the attack but said the rebels had been defeated.

"They suffered heavy losses. Twenty-five fighters of the Justice and Equality Movement were killed, 10 of their trucks were destroyed," he said, adding that JEM had earlier attacked a market in the area and stolen goods.

Such casualty claims are impossible to verify from a region where access is restricted.

Violence in Darfur, where the United Nations and the African Union maintain a huge joint peacekeeping operation, has subsided since its peak in 2003 and 2004, but rebel and tribal fighting has continued.

In April, the head of the African Union-United Nations peacekeeping mission in Darfur (UNAMID) expressed concern that the region's rebels were exploiting tensions between Sudan and South Sudan along their disputed frontier.

JEM and other Darfuri rebel factions belong to a "Revolutionary Front" which aims to topple the government in Khartoum, which they regard as unrepresentative of the country's political, ethnic and religious diversity.

Khartoum alleges that South Sudan backs JEM and other rebels, a charge the Southern government denies and in turn accuses Sudan of supporting insurgents south of the border.

The Sudanese government puts the death toll at 10,000. Almost two million people are still displaced.