The army of the Democratic Republic of the Congo accused M23 insurgents on Thursday of killing 50 civilians and violating a five-day truce in the country's restive east.

The ceasefire went into effect in North Kivu province over the weekend, following a summit between the DRC and its neighbor Rwanda. It was supposed to be followed by a rebel withdrawal from captured territory, which has yet to occur.

General Sylvain Ekenge stated that the M23 group was "carrying out massacres... the most recent of which was the heinous murder of 50 Congolese civilians on Tuesday in Kishishe," a village 70 kilometers (40 miles) north of the eastern city of Goma.

While Congolese forces "scrupulously observed the truce," the M23 attacked government positions, Ekenge claimed.

According to sources, fighting resumed Thursday in Kirima, a town in the same region about 10 kilometers (six miles) from Kibirizi. "The rebels have crossed the bridge, heading for Kibirizi," said Paul Lutibahwa, head of civil society groups in the Bambo region.

A security official, speaking on condition of anonymity, accused the M23 of having breached the ceasefire and "carrying on looting and fighting."

A DRC army officer, who also asked not to be identified, said, "The fighting is heavy -- we are using heavy artillery." Willy Ngoma, the M23's military spokesman, confirmed the fighting with the army when contacted by AFP.

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This comes after M23 rebels were still fighting and advancing in eastern Democratic Republic of Congo on November 25, according to civilian and military sources, just hours before a ceasefire was set to go into effect.

Local sources told AFP by phone that clashes were taking place in Bambo, 70 kilometers (45 miles) north of the provincial capital Goma. "Heavy weapons fire can be heard, people are in a panic," a civil society representative said.

According to a security source, the M23 fired on combatants from the Democratic Forces for the Liberation of Rwanda (FDLR).

Fighting was also reported near Bwiza in the morning. However, the situation appeared more settled 20 kilometers north of Goma, where a frontline has formed over the last two weeks close to the town of Kibumba on national highway two.