Chad's government says it has regained control of two eastern villages after rebel advances on Sunday. Meanwhile, several Chadian rebel groups appear to have reached a new unity accord.
Humanitarian workers in Eastern Chad say rebel forces entered the town of Goz Beida after midday Sunday, firing weapons into the air.
The Chadian government says it retook control of Goz Beida and another nearby village soon after. There are no reports of casualties.
The rebels advanced hours after one of their leaders announced a new coalition of three main rebel groups opposed to Chadian President Idriss Deby.
Analyst Adrien Feniou, of the Boston-based Global Insight, said that agreement is not likely to hold.
"There have already been several attempts at merging the various movements, but they are so plagued with tribal affiliation, ethnic affiliation that they very easily disintegrate," he said.
Aid workers in Eastern Chad say rebels began attacking and burning villages in recent weeks, killing more than 100 people.
The rebels are in an apparent alliance with so-called janjaweed militias from Sudan.