Refugees fleeing eastern DRC last week reported heavy gunfire as government forces clashed with fighters loyal to war crimes suspect Bosco Ntaganda.
The International Criminal Court in 2010, in an unsealed indictment, accused Ntaganda, a former military commander, of crimes committed in the DRC. The ICC said there was "reasonable grounds to believe" he played a direct role in conscripting child soldiers.
Ntaganda was believed to be preparing for a full-scale rebellion and the BBC reports another senior military commander has joined the rebel commander.
Military forces, however, said the eastern DRC was "secured" and rebels were given until Wednesday to surrender, the British broadcaster adds.
DRC was marred by violence following presidential elections in November. Navi Pillay, U.N. high commissioner for human rights, said earlier this year that she heard "multiple accounts" of national forces using live ammunition on demonstrators during the election season.