A government official says that rebels have seized Sibut, 185 kilometers (114 miles) from Bangui, the capital.
Minister of Territorial Administration Josie Binoua said the rebels took Sibut on Saturday morning. Chadian army forces were based alongside the CAR army in Sibut but the city was taken without a fight because all the defense forces pulled back to Damara, 75 kilometers (46 miles) from Bangui on Friday.
The telephone lines to Sibut have been cut, making it difficult to check the situation with local residents.
The news of the rebels taking Sibut comes as regional African countries have agreed to send more forces to support the government of President Francois Bozize. Talks between the rebels and the Bozize government are planned to start next week in Gabon.