KINSHASA, Congo (AP) — Authorities in Congo say five park rangers and a driver have been killed in an attack at the Virunga National Park.

The park, which is home to critically endangered mountain gorillas, confirmed the ambush Monday in a statement. It said a sixth ranger was wounded.

There was no immediate claim of responsibility. However, suspicion immediately fell on militia groups that are active in and around the famed wildlife park. Virunga, a UNESCO World Heritage site, is home to about one-fourth of the remaining mountain gorillas in the wild.

The gorillas are poaching targets and their habitat is being destroyed by deforestation in part to supply charcoal. Human rights groups say armed groups are controlling the industry to support a rebellion.