GOMA (Reuters) - Militiamen have killed a ranger in Congo’s Virunga National Park, the park said on Friday, less than a month since it re-opened after being shut down because of insecurity.

Virunga, abutting the forest-cloaked volcanoes of the western Rift Valley, is home to over half the world’s population of mountain gorillas and other unique species like the golden monkey. It was closed for eight months after gunmen kidnapped tourists and killed a ranger trying to defend them last May.

Ranger Freddy Mahamba Muliro was killed on Thursday while protecting a security post, one of 176 rangers to have been killed protecting the park since it was established in 1925, Chief Warden Emmanuel Merode said.

The identity of the assailants remained unclear on Friday.

“We are in deep mourning,” Merode said in a statement. “Ranger Freddy’s death marks another devastating loss for our rangers.”

Warfare in eastern Democratic Republic of Congo between 1996 and 2003 killed millions of people, mainly through hunger and disease. Since tourism was relaunched in 2014, Virunga has received more than 17,000 visitors.

But armed militias still control large swathes of territory in and around it.