New, intense clashes between the Chadian army and rebels have erupted in eastern Chad, not far from the Sudanese border.

Army and rebel sources say the fighting Thursday was centered in the Hadjer Marfain mountains, about 150 kilometers northeast of the city of Abeche.

Details on the fighting are sketchy, although sources from the rebel group,the Union of Forces for Democracy and Development, describe the clashes as violent.

The army and rebels fought an intense battle on Monday in which both sides claim to have killed hundreds of their opponents. On Wednesday, the Chadian government said its army had chased and destroyed rebel fighters who escaped Monday's fighting.

There has been no independent confirmation of any of the claims.

The clashes followed the collapse of the cease-fire the Chadian government and four major rebel groups signed last month in Libya.

Two rebel groups announced Friday that they would break the cease-fire, and they accused the government of President Idriss Deby of failing to keep promises in the truce agreement.

The European Union plans to deploy more than 3,000 peacekeepers in eastern Chad early next year. That force is meant to protect relief operations for hundreds of thousands of people displaced by violence in Darfur and Chad.

Some information for this report was provided by AFP and Reuters.