Fierce fighting has erupted between M23 rebels and militiamen in the eastern Democratic Republic of Congo, local sources said reporting an unconfirmed number of fatalities. 

One of the sources, who spoke on condition of anonymity, said he was aware of around 100 victims following the violence which broke out on Tuesday. 

Since the agreement of a ceasefire at a summit in Luanda on November 23, there have been no reports of fighting between the M23, which occupies swathes of territory in North Kivu province, and the Congolese army. 

But clashes continue between the Tutsi rebel movement and various militias backed notably by the Hutu FDLR (Democratic Forces for the Liberation of Rwanda) movement.

According to witnesses interviewed by telephone, fighting took place on Tuesday in the town of Kishishe about 70 kilometres north of Goma, the capital of North Kivu province.

M23 fighters clashed with a community militia associated with the FDLR called Mai-Mai. 

"The Mai-Mai were numerous, coming from Kibirizi (about 20 kilometres from Kishishe), they had arrows, knives, machetes," one resident said. 

"From there the fighting ensued with M23s firing throughout the night. I managed to escape but two members of my family were killed," he said.  

"Many people were killed yesterday in Kishishe, most of them civilians," said a civil society member. 

"The Mai-Mai fought in civilian clothes. They attacked the M23 as they came out of civilian houses," he said. 

"The M23 thought those in the houses were Mai-Mai and they killed them," he said. 

"The toll given to us is 102 dead, but we don't have exact figures because most of the civilians have fled the area," said a civil society representative in Kibirizi. 

He said the Mai-Mai "numbered around 100 and joined the FDLR in attacking". 

"They have returned to Kibirizi, because we hear that M23 is advancing towards here," he added. The M23, a former Tutsi rebel group defeated in 2013, took up arms again late last year. 

Since then, Kinshasa has accused Kigali of supporting the rebels, a charge Rwanda has denied.