* Rebel factions fight with regional talks stalled
* M23 faction says to arrest rebel wanted by ICC
* Kinshasa may target divisions with military push (Adds details of fighting, quotes)
By Jonny Hogg
KINSHASA, Feb 28 (Reuters) - Fighting erupted between two factions of Congo's M23 rebels near the eastern town of Goma on Thursday after one side said it sent men to arrest a leader of the other, Bosco Ntaganda, who is wanted on international war-crimes charges.
M23's military command said its political coordinator Jean-Marie Runiga had been sacked for backing Ntaganda, highlighting divisions that threaten regional efforts to end two decades of conflict in the restive borderlands zone of central Africa.
The M23 revolt is the latest uprising in Democratic Republic of Congo's mineral-rich east. Last year the group inflicted a series of embarrassing defeats on government forces, culminating in the brief seizure of Goma, a strategic border town.
A Reuters witness in Goma said heavy weapons fire could be heard coming from the direction of rebel positions around Kibumba, some 25 km (14 miles) north of Goma.
"We heard lots of firing. It was between (M23 military chief Sultani) Makenga's men and Ntaganda's men. It's Makenga's men who control the town now," a motorbike taximan, Innocent Bishimwa, told Reuters on the southern outskirts of Kibumba.
A commander of the faction loyal to Makenga said later they had successfully driven Ntaganda's forces out of Kibumba.
"The men of Ntaganda barricaded the route north of Kibumba to block our men, but our men have been able to push through the barricade and although fighting is continuing, all of Ntaganda's men have been dispersed," Colonel Vianney Kazarama said.
The emerging power struggle within rebel ranks will further damage efforts to revive peace talks hosted by Uganda and may spur the Kinshasa government to push for a military solution to recurring rebellions in the east.
"This plays into Kinshasa's hands, either because they're using it to strike a deal with some elements of M23, or because they can take advantage of their weakness to launch a military strike," Jason Stearns, director of the Rift Valley Institute think-tank, said.
M23's military command said Runiga was ousted for stealing money and backing the rebel faction loyal to Ntaganda, a fighter wanted by The Hague-based International Criminal Court on charges of killing civilians during a previous uprising.
The statement, signed by Makenga, said he would become the group's interim leader. Runiga was unavailable for comment. He said earlier there were no issues between himself and Makenga.
Kazarama said Makenga's fighters had been dispatched to arrest Ntaganda in an area north of Goma on Thursday.
Colonel Seraphin Mirindi, spokesman for the faction loyal to Runiga and a pro-Ntaganda member of the group, warned: "We have the right to defend ourselves," adding that they had been attacked by the Makenga faction.
U.N. experts say Ntaganda has played a major command role within M23. This has been denied by the rebels.
Thierry Vircoulon of the International Crisis Group think tank said of the power struggle: "I wouldn't say there's a good guy and a bad guy, but there's one who is more manageable, and the other who is wanted by the ICC. It's another argument for Kinshasa to perhaps go for the military option."
In a separate incident on Thursday, fighting flared between Congolese troops and another rebel group, APCLS, in Kitchanga, North Kivu, on Wednesday in which 36 people were killed, including 10 civilians, the U.N. mission in Congo said.
Goma's seizure in November embarrassed Congo's government and U.N. peacekeepers deployed to support Kinshasa's forces.
U.N. experts accused neighbouring Rwanda of backing the rebels. Kigali, which has repeatedly intervened in chaotic Congo's conflicts since Rwandan Hutu rebels sought refuge in the lawless east after the 1994 genocide, denied the charge. (Reporting by Jonny Hogg; Writing by David Lewis; Editing by Mark Heinrich)