This file photo taken on November 13, 2018, shows Tanzanian soldiers from the United Nations Organization Stabilization Mission in the Democratic Republic of the Congo (Monusco) patrolling against Ugandan Allied Democratic Force (ADF) rebels in Beni.
"The enemy ADF (Allied Democratic Forces) ambushed farmers at around 4 pm (1400 GMT) on Friday near the village of Enebula," local civil society leader Patrick Mukohe told AFP by phone.
Mukohe said he had counted 21 bodies of men and women at the site of the killing, some 30 kilometres (20 miles) west of the town of Oicha, in North Kivu province.
Jules Kambale, who works in the Oicha hospital morgue, said it had received 19 bodies.
Charles Ehuta Omeanga, the regional military administrator, confirmed the attack, which he attributed to "ADF terrorists", but said he was not in a position to give a definitive toll.
The ADF, originally insurgents in Uganda, gained a foothold in eastern Democratic Republic of Congo in the 1990s and has since been accused of killing thousands of civilians, becoming the deadliest of scores of outlawed forces in the deeply troubled region.
Since 2019, some ADF attacks in eastern DRC have been claimed by the Islamic State, which describes the group as its local offshoot, the Islamic State Central Africa Province.
In a video shared on social media, and authenticated by Mukohe, a crowd surrounds the body of a man tied to a wooden frame, his throat slit.
When the bodies of victims arrived at the Oicha morgue, some youths tried to block the nearby national road in protest.
They were quickly dispersed by the police who, according to one civil society source, fired bullets in the process.
"The situation here is catastrophic," the source said.
On Thursday, the United Nations mission in the country, MONUSCO, said that more than 30 people had been killed by the ADF in neighbouring Ituri province earlier in the week.
Last month, the United States offered a reward of up to $5 million for information concerning ADF leader Seka Musa Baluku.