An attack blamed on Islamic State-linked rebels has left dozens of people dead in eastern Democratic Republic of Congo's Beni region, local authorities said on Thursday.

Colonel Alain Kiwewa Mitela, a local official in Lubero territory where the overnight attack occurred, told AFP that 42 bodies had been found.

It brings to nearly 150 the number of people killed since the start of the month by rebels of the Allied Democratic Forces, according to figures from local authorities and civil groups.

A civil society leader, Seba Paluku, told AFP there were 41 bodies, including some that were "tied up" and "decapitated.”

He said he had gone to the site with soldiers. "The bodies are lying still on the ground. There's no means of transporting them because vehicles can't get there,” he said.

Samuel Kakule, a civil society leader in Mangurujipa, not far from the site of the attack, said that "around 2 p.m. yesterday, we were told of the presence of the enemy" and that later "they fired on the peaceful population, and the bodies began arriving at the hospital.”

Between June 1 and 11, the Islamic State group claimed responsibility for about 15 attacks on villages and roads near Beni that have killed 125 people, almost all of them civilians.

A local official estimated the number to be 109 while a security official said it stood at 138.

The Allied Democratic Forces, or ADF, historically a Ugandan Muslim majority rebel coalition, has established a presence over the past three decades in eastern Democratic Republic of Congo, killing thousands of civilians.

It pledged allegiance in 2019 to the Islamic State group, which portrays the ADF as its central African branch.

Since the end of 2021, the Congolese and Ugandan armies have conducted joint operations against the ADF in North Kivu and neighboring Ituri province but have so far failed to stop the deadly attacks on civilians.

The east of the country has been plagued by violence by armed groups for decades.

The Rwanda-backed March 23 Movement resumed its armed campaign in the region at the end of 2021, seizing swathes of territory in North Kivu, as intensified fighting continues to displace tens of thousands of people.