Rebels in Sudan's Darfur region say they have come under heavy attack by government troops with many dead and injured.
Reports from at least two rebel groups in the area say the government launched an attack Saturday on rebel bases in the town of Disa in north Darfur.
The rebels say the government used four helicopter gun ships and two Russian-made Antonov airplanes in the attack, along with ground troops and vehicles. The rebels say casualties were high but no numbers could be confirmed.
The Sudanese army was not available for comment.
A spokesman for the joint U.N. - African Union peacekeeping force in Darfur (UNAMID) said they are investigating the reports.
More than five years of fighting in Darfur among rebel groups, the government and government-allied militias have killed more than 200,000 people and displaced more than 2.5 million others.
Some information for this report was provided by AFP and Reuters.