Congolese insurgents loyal to the warlord Bosco Ntaganda have fled into neighboring Rwanda or surrendered to U.N. peacekeepers after being routed by a rival rebel faction, sources said on Saturday.

M23 fighters loyal to Sultani Makenga seized control of the strategically important town of Kibumba, 30 km (19 miles) north of the provincial capital Goma, early on Saturday, rebel spokesman Vianney Kazarama told Reuters.

Ntaganda and an estimated 200 fighters fled into nearby forests, whilst others went to Rwanda, he said.

"We're sweeping the area and placing our soldiers at strategic points," Kazarama said. "It is finished."

Rwandan military spokesman Brigadier General Joseph Nzabamwita said that fighters had entered Rwanda from eastern Democratic Republic of Congo but he could not confirm their identities.

"There are some fighters who have crossed the border. The situation is very fluid," he said.

A U.N. source said dozens of M23 fighters loyal to Ntaganda, who is wanted by the International Criminal Court for war crimes and crimes against humanity, had handed themselves over to peacekeepers in recent days.