Gen Laurent Nkunda has been accused of committing war crimes
Rebel commanders in eastern Democratic Republic of Congo have pledged their loyalty to Gen Laurent Nkunda, following claims he had been toppled.
His spokesman said those rebel officials saying he had been ousted had committed "high treason".
A BBC correspondent says a rebel split could make the DR Congo conflict even more unpredictable and dangerous.
Last year's offensive by Gen Nkunda's forces left some 250,000 homeless and raised fears of a regional war.
The area has been relatively quiet in recent weeks but BBC World Affairs correspondent Mark Doyle says a split in the National Congress for the Defence of the People (CNDP) rebel group could reignite the conflict.
Those loyal to Gen Nkunda held a crisis meeting in the Rutshuru area of North Kivu province, some 60 km (40 miles) north of the provincial capital Goma, reports the AFP news agency.
They also sent a delegation to regional peace talks in the Kenyan capital Nairobi, due to resume on Wednesday.
WHO IS BOSCO NTAGANDA?
Said to be a hardliner, known as "the Terminator"
Indicted for war crimes by ICC, for conscripting children to fight
Previously member of UPC, whose leader Thomas Lubanga is detained by the ICC in The Hague
Refused army post in 2004
Joined Gen Nkunda's CNDP two years later
"All the institutions and all the organs of the movement remain loyal to General Laurent Nkunda. Our leader has not been ousted," CNDP spokesman Bertrand Bisimwa told the BBC.
But supporters of Brig Gen Bosco Ntaganda, who had announced Gen Nkunda's ousting, held a separate meeting near Masisi, further west, according to AFP.
A statement sent to the BBC and signed by Gen Ntaganda had accused Gen Nkunda of "bad leadership" and "bad governance".
Known as "the Terminator", Gen Ntaganda has been indicted by the International Criminal Court in the Hague, which accuses him of conscripting children as young as 15 into his forces.
Gen Ntaganda has a long history of serving in various armed groups, including the UPC of Thomas Lubanga, who the ICC is holding in The Hague.
He was offered a senior military post by the Congolese government in 2004 but refused. Two years later he joined Gen Nkunda.
Reported to be among the most hardline in the CNDP, Gen Ntaganda is said to have been critical of Gen Nkunda on two grounds: That he failed to press home his attack on the eastern town of Goma late last year; and that he has supported a ceasefire, which has allowed the government to bolster its position on the ground.
One report says the pair fell out following last November's massacre of at least 150 people in Kiwanja, where Gen Ntaganda was the local CNDP military leader.
Gen Nkunda and his group say they are fighting to protect the Tutsi community from attack by Rwandan Hutu rebels based in DR Congo, some of whom are accused of taking part in the 1994 genocide.
The Congolese government has often promised to stop the Hutu forces from using its territory, but has not done so.
But others see the CNDP as a Rwandan proxy and the main reason why DR Congo has yet to benefit from landmark elections in 2006 that were intended to draw a line under decades of conflict.
Human rights groups have accused CNDP forces, along with those of the government, of numerous killings, rapes and torture.
Gen Nkunda has also been accused of war crimes.