About one-hundred troops from the Democratic Republic of Congo have crossed the Oubangi river from Bangui, in the Central African Republic, in their battle for control of the northern Congolese town of Zongo.
An unconfirmed report on Radio Rwanda said Congolese rebels had captured the town.
The troops were among three-hundred who flew across northen Congo into Bangui on Sunday.
Correspondents say the government of Laurent Kabila has the political support of the Central African Republic
From the newsroom of the BBC World Service