Assailants killed three rangers and another member of their convoy in an ambush in the volatile east of the Democratic Republic of the Congo, according to the Congo Institute for Nature Conservation (ICCN).

The attackers struck on Thursday as the convoy, escorted by ICCN rangers, left Kivandya village near Virunga National Park, which is home to half the global population of endangered mountain gorillas and the scene of frequent militia attacks.

The fourth victim was one of the technical workers implementing a project to support communities around Virunga, ICCN said in a statement late Thursday.

A further six people were wounded, it said.

Virunga has been caught in the middle of militia activity that has destabilised the surrounding South Kivu province since civil wars were fought around the turn of the century.

The ICCN warned of a resurgence of violence in February after suspected Mai Mai militants attacked a ranger position in Virunga, killing one person and injuring two.

The eastern DRC has been plagued by fighting by at least 122 rebel groups – according to a recent count by the United Nations – for more than 25 years.