The Allied Democratic Forces (ADF) is the main militia force operating in eastern DR Congo and has been carrying out reprisal attacks on civilians in response to a crackdown by the military, known as FARDC.

"A joint operation against ADF has allowed the FARDC to capture 40 fighters close to Makeke," Lieutenant-Colonel Claude Raoul Djehoungo, a MONUSCO spokesman said.

The operation in the Beni region on February 9 came after at least seven civilians were killed in the latest suspected ADF massacre in the area.

More than 300 people have been killed in ADF attacks in eastern DR Congo since the end of October when the army began its operations against the militia group.

Senior Congolese army officials neither denied nor confirmed the capture or detention of 40 ADF combatants by the regular forces.

The ADF, blamed for the deaths of more than 1,000 civilians in Beni since October 2014, began as an Islamist-rooted rebel group in Uganda that opposed President Yoweri Museveni.

It is one of several local militias operating in the area -- a legacy of the two 1990s Congo wars that dragged in DR Congo's neighbours into a regional conflict.