Armed men on Sunday killed at least six rangers and wounded several others in an ambush in eastern Democratic Republic of Congo’s Virunga National Park, a sanctuary for endangered mountain gorillas, the park said. Previous attacks against the rangers have been blamed on various militias who fight to control land and natural resources in eastern Congo. More than 200 rangers have been killed in the past, including 12 last April in the deadliest such attack in recent memory. Dozens of armed groups operate in eastern Congo, many remnants of militias that fought in civil wars around the turn of the century that resulted in millions of deaths from conflict, hunger and disease. Virunga National Park sits on the forest-covered volcanoes of central Africa and is home to over half the global population of mountain gorillas. A UNESCO World Heritage Site since 1979, it is Africa’s oldest national park and largest tropical rainforest reserve, covering 7,800 sq km with a varied landscape of active volcanoes, savannahs, mountains, lakes and forests.