KHARTOUM, Sudan (Reuters) -- Rebels in Sudan's Darfur said on Saturday they had captured an area in the east of the war-torn region after defeating government forces, but the army said the insurgents had simply looted from civilians there.

Darfur has been plagued by violence since rebels took up arms against the government in 2003, accusing Khartoum of marginalizing the remote region.

The government sent troops and allied Arab tribes to quell the insurgency, unleashing a wave of violence which the United Nations and other observers estimate has killed hundreds of thousands of people.

While fighting has subsided since its peak in 2003 and 2004, law and order have broken down in many parts of the region and clashes between insurgents and government forces have continued despite a large U.N. peacekeeping force in the area.

The Justice and Equality Movement, widely considered to be Darfur's most powerful rebel force, said it took control of the Umm Ajaja area in eastern Darfur on Friday.

It said it captured several military vehicles and took a number of prisoners from "the regime's militias".

But Al-Sawarmi Khalid, Sudan's armed forces spokesman, rejected this, saying there had been no clashes between the army and rebels because there had been no troops in the area at the time.

"What happened is that a force from the Justice and Equality Movement attacked the area and looted the possessions of the citizens," he said.

Last year, JEM joined other rebels in Darfur and the southern Sudanese border states of Blue Nile and South Kordofan in an alliance which aims to topple President Omar Hassan al-Bashir.

On June 2, JEM said it had attacked an army camp in northeastern Darfur, killing several soldiers. The army confirmed the attack took place, but said the rebels had been defeated.