ADF rebels armed with machetes and hoes have killed at least 52 civilians in the Beni and Lubero areas of eastern Democratic Republic of Congo in recent days, UN and local officials said.

The Allied Democratic Forces (ADF) rebels were taking revenge on civilians after suffering defeats by Congolese forces, Lieutenant Elongo Kyondwa Marx, a regional Congolese army spokesperson, said.

"When they arrived, they first woke the residents, gathered them in one place, tied them up with ropes, and then began to massacre them," Macaire Sivikunula, chief of Lubero's Bapere sector, told Reuters over the weekend.

About 30 civilians were killed in the village of Melia alone, Alain Kiwewe, a military administrator for the Lubero territory, told Reuters.

Women and children among victims

"Among the victims were children and women, while several houses were set on fire," he said.

The United Nations Organization Stabilization Mission in the Democratic Republic of the Congo (MONUSCO) condemned "in the strongest possible terms" the attacks by the ADF between August 9 and 16, the mission's spokesperson said on Monday.

The attacks killed at least 52 civilians, including eight women and two children, and the toll could rise as the search is ongoing, the spokesperson said.

The ADF is among several militias wrangling over land and resources in DR Congo's mineral-rich east.

Anti-ADF operations

DR Congo's army and its ally, Uganda, have intensified operations against the ADF in recent weeks.

In late July, ADF rebels killed 38 people in an attack on a church in eastern DR Congo.