Rebels claim to have captured a town in the far north-east of the Central African Republic (CAR).
A force of around 150 rebels took the town of Birao, which is close to the border with Sudan and Chad.
The rebels from the UFR movement say some government troops joined them, and others were taken prisoner.
In April this year an Antonov plane, carrying rebels, landed in the same location. The CAR government accused Sudan of being behind that attack.
Observers say the town, which is in a remote and swampy location, has been used by rebels as a base to attack the government.
Refugees from CAR fled fighting into Chad earlier this year
"We took control of Birao early this [Monday] morning at 4:00 am [0300 GMT]. There was brief fighting," Abakar Sabone, who called himself a UFR captain, told the AFP news agency by telephone.
Security in the north has deteriorated in the past year, due to an increase in robberies and the emergence of rebels seeking to overthrow President Francois Bozize.
The town is also close to Chad and Darfur which have witnessed violence and insecurity in recent years.