Militants ambushed a group of about 30 civilians in northeastern Congo and killed many of them before fighting a fierce battle with the army, politicians said on Sunday.
The attack took place near the city of Beni and, if the deaths are confirmed, would be the first mass-killing this year in that area. It has seen relative peace since more than 800 people were killed in dozens of massacres between 2014 and 2016.
The spate of attacks raised serious questions about the state's ability to impose order over a region full of ethnic tensions and plagued by pockets of lawlessness where armed groups prey on populations and exploit rich mineral reserves.
In the latest attack, on Saturday, assailants armed with machetes and guns ambushed travelers on the main road linking Beni in North Kivu province to neighboring Ituri province, Boris Maelezo, a member of parliament from the area, told Reuters.
He said about 30 civilians were riding on motorbikes, with several people on each vehicle, and that most of them could have been killed.
Albert Baliesima Kadukima, another lawmaker from the area, said two women freed by the militants had told local authorities the assailants had slit the throats of more than a dozen people.
Mak Hazukay, a local army spokesman, said Congolese forces were battling the militants and attempting to dislodge them from a section of the road that was several kilometers long.
The two lawmakers and the army spokesman said the militants belonged to the Allied Democratic Forces (ADF), a Ugandan Islamist group active near the border between Congo and Uganda.
Eastern Congo is a tinderbox of ethnic tensions and has been racked by conflict for more than two decades. It is the world's biggest source of coltan, used in mobile phones and other electronic products.
Various armed groups have committed atrocities around Beni since late 2014 to settle scores and undermine rivals, with attacks sometimes sectarian in nature.