Rebel commanders pledged their loyalty to Laurent Nkunda this week
Congolese rebel leader Gen Laurent Nkunda has told the BBC disciplinary action is being taken against a commander who tried to oust him.
But he said his chief-of-staff would not be executed for claiming on Monday he had been toppled. Gen Nkunda said he was guilty of a "fall", not a betrayal.
His remarks came as renewed talks got under way in Kenya on the future of eastern Democratic Republic of Congo.
A fragile ceasefire is in force between government and rebel troops.
The talks, scheduled to last 10 days in Kenya's capital Nairobi, are aimed at making the current ceasefire in the east of the country permanent.
The UN mediating team, led by the former Nigerian President Olusegun Obasanjo, declared that there must be progress in the discussions.
When the talks broke up in December, Mr Obasanjo complained that negotiators from Gen Nkunda's rebel Congress for the Defence of the People (CNDP) had no authority to make even basic decisions.
The BBC's Peter Greste in Nairobi says Mr Obasanjo is understood to be in DR Congo, meeting Gen Nkunda.
The meeting may be more to assess just how much control Gen Nkunda has over his organisation than to discuss questions of authority, says our correspondent.
Fighting flared in eastern DR Congo late last year when rebel forces seized new territory, leaving some 250,000 people homeless, before agreeing to a halt in the fighting.
Gen Nkunda told the BBC that Brig Gen Bosco Ntaganda remained chief-of-staff, but would face a disciplinary hearing on Thursday.
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
"I think that there is no problem in the [CNDP] party and there is someone, a cadre, a member, even at a high level, who set about changes," he told the BBC's Focus on Africa from his Rutshuru headquarters in eastern DR Congo.
"Maybe let us watch how and why he did it because tomorrow there is a meeting of the disciplinary committee of the high command so that they can give him a chance to explain himself."
Asked if Gen Ntaganda would be executed, Gen Nkunda replied: "He did so many things to the movement, even he can do one case of indiscipline. It's not a betrayal, no, it's a fall."
A statement sent to the BBC and signed by Gen Ntaganda on Monday had accused Gen Nkunda of "bad leadership".
But a day later rebel commanders pledged their loyalty to Gen Nkunda.
Gen Ntaganda is said to have been critical of Gen Nkunda for failing to take the town of Goma late last year; and for agreeing the truce, allowing the government to bolster its position.
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.
But others see the CNDP as a Rwandan proxy and rebel forces have been accused, along with those of the government, of murder, rape and torture.