JOHANNESBURG (AP) — A wildlife park in eastern Congo that is home to critically endangered mountain gorillas will remain closed to tourism following an attack in which two British tourists were abducted and later released.

Virunga National Park, which halted tourism after the May 11 incident in which a ranger was killed, said Monday that the restriction will continue until "further notice."

On April 9, six park staffers were killed in an ambush in Virunga. Numerous armed groups operate in Eastern Congo, a resource-rich area that has long been in conflict.

Virunga park managers say they have received more than 17,000 visitors since relaunching tourism in 2014, and that the industry is key to supporting local communities.

The park's struggles were the subject of a 2014 documentary that was nominated for an Oscar.