Democratic Republic of Congo's M23 rebels have declared a ceasefire after a 20-month rebellion in North Kivu province to allow peace talks with the government to advance.

Bertrand Bisimwa, leader of the M23 rebel group, urged all fighters on Sunday to "immediately end hostilities" with the government troops.

"We call on the facilitator of the Kampala peace talks to immediately put in place a mechanism to monitor the ceasefire," Bisimwa said in statement.

There was no immediate reaction from the army.

The declaration of the truce came on the day when the government troops said it launched a new offensive against rebel fighters who fled to the hills around Congo's border with Uganda and Rwanda after being ousted from Bunaguna, their last stronghold.

On Friday, Uganda, which has led regional attempts to end the most serious rebellion since Congo's last war ended a decade ago, called for both sides to stop fighting.

Heavy fighting has eased, but the army said it shelled rebel positions on Saturday to encourage fighters to surrender.

Congo's government has dispatched senior negotiators to talks in Uganda, but the army is keen to finish off the rebellion, the last in a series of uprisings led by Congolese Tutsis in the mineral-rich but unstable east.

Source: Agencies