The rebels from the M23 group said they were declaring the ceasefire on Sunday in the hope that it would help advance peace talks with the government.

"We call on the facilitator of the Kampala peace talks to immediately put in place a mechanism to monitor the ceasefire," the rebels said. Peace talks, officially facilitated by Ugandan Defense Minister Chrispus Kiyonga, have been taking place in the Ugandan capital Kampala, although fighting has continued at the same time. Kiyonga on Friday called for the fighting to stop.

M23 president Bertrand Bisimwa said in a statement his aim was to "allow the continuation of the political process" with the government in Kinshasa.

Government troops, with the support of a UN intervention force, on Wednesday seized the key town of Bunagana, which had been the main M23 base near the eastern border with Uganda.

The army said earlier on Sunday that it was launching an offensive in the mountains near the town, where the rebels had fled.

"We are pounding Mbuzi," General Lucien Bahuma told the news agency AFP, referring to one of three mountains where the rebels have taken refuge.

Rwanda, which has been accused of supporting the M23 rebels, is also involved in the talks.

The M23 movement, also known as the Movement of March 23, was set up by ethnic Tutsi rebels who had been incorporated into the Congolese army as part of a 2009 peace deal. The agreement was signed on March 23 of that year, but the rebels mutinied in April 2012, claiming the terms of the treaty had been broken.

rc/dr (AFP, Reuters)