Two soldiers were killed in fighting against M23 militants in eastern Congo on Monday, the army said - the latest violence in a long-standing conflict that has escalated in recent weeks and caused a diplomatic rift with Rwanda.

The rebels shelled an army position in North Kivu, killing two soldiers and injuring five. Congo accuses the neighbourung state of supporting the M23, which Rwanda denies.

That clash followed a raid on a village in neighbouring Ituri province on Sunday by suspected Islamists from another rebel group that killed at least 18 people, local sources said.

Fighters believed to be from the Allied Democratic Forces (ADF) killed residents and burned down houses in Otomabere, said a witness, a local chief and a local human rights group.

Congolese army spokesman Jules Ngongo confirmed the ADF attack without giving a death toll, and said Congolese forces were in pursuit of the rebels.

The ADF is a Ugandan militia that moved to eastern Congo in the 1990s and killed more than 1,300 people between January 2021 and January 2022, according to a United Nations report.

"We were chatting with some friends outside (when) we heard gunshots, and everyone fled in a different direction. It was total panic," said Kimwenza Malembe, a resident of Otomabere.

"This morning we counted 18 dead, killed by knives and firearms."

Irumu chief Jonas Izorabo Lemi said he had received word of 20 dead.

Christophe Munyanderu, coordinator of the local group Convention for the Respect of Human Rights (CRDH), put the death toll at 27, up from a provisional figure of 20.

Uganda has sent at least 1,700 troops to neighbouring Congo to help fight the ADF, and last week the two countries extended a joint operation launched late last year.