The largely ethnic Tutsi M23 rebel militia has seized swathes of the Democratic Republic of Congo's troubled east since 2021, displacing thousands while creating a humanitarian crisis.

A ceasefire agreement signed in August had stabilised the situation at the front.

But since the end of October the M23 has been again on the march in the North Kivu province, heading toward the strategically important loyalist town of Pinga.

On Sunday the rebels went on the attack in Lubero territory towards Lake Edward that forms part of the DRC's border with Uganda, according to several local and military sources contacted by telephone by AFP.

Following fighting with the Wazalendo, a disparate coalition of militias backing the Congolese army, rebels seized the town of Kamandi Gite on the shores of the lake, the sources said.

The DRC has accused Rwanda and the M23 of abusing the truce to seize territory before the monitoring mechanism comes into force.

Truce-negotiator Angola said Friday that it would lead the observing force, which will include both Congolese and Rwandan officers.

In Pinga, a Wazalendo stronghold home to one of the region's few airstrips, calm returned after the DRC's army and its allied militias clashed with M23 fighters near the town last Thursday.

But over the past few days many displaced people fleeing the M23 have poured into the town, swelling Pinga's population.

"The hospital has no medicine, the toilets are in a bad state and access to water is a problem. We fear the appearance of serious illnesses... that will be difficult for us to treat", Theophile Mukandirwa, director of the Pinga hospital, told AFP.

Home to a string of rival rebel groups, the mineral-rich eastern DRC has been plagued by internal and cross-border violence for the past three decades.