Government officials in Chad say their forces have regained control of a major town that rebels said they had occupied on Tuesday.

The exact situation in the central town of Mongo remains uncertain, with rebel leaders telling news agencies that some rebel forces remain inside the town.  Chad's defense minister Issa Djadallah says government forces used helicopters to disperse the rebels.

The insurgent United Front for Change is seeking the overthrow of Chad's President Idriss Deby.  The raid on Mongo is the closest rebels have come to the capital, N'Djamena, about 400 kilometers to the east.

On Monday, rebels raided the Goz Amer refugee camp in eastern Chad and killed several government security officers. 

The rebel movement includes former government soldiers who defected from the army.  Mr. Deby has accused neighboring Sudan of backing the rebels, a charge Khartoum denies. 

Mr. Deby won power in a 1990 coup.  He later won two elections and is running for a third term in voting scheduled for May 3.

The U.N. refugee agency, which runs camps for Sudanese refugees in eastern Chad, says it will begin evacuating its staff from the region.