NAIROBI, Kenya — Twelve rangers were among 17 people killed in Virunga National Park in the Democratic Republic of Congo, officials said, in one of the worst massacres in the park’s recent history. The park blamed members of a Rwandan rebel group for the attack.

The rangers were on their way back to the park, the oldest in Africa, when they spotted a civilian vehicle that had been attacked and came to its defense, park officials said in a statement. But they came under “a ferociously violent and sustained ambush” about 11 a.m. on Friday near Rumangabo village, according to the statement.

Aside from the rangers killed, a driver and four civilians were shot dead. Two other civilians and four rangers were injured, with one in critical condition.

“This is a devastating day for Virunga National Park and the surrounding communities,” the park officials said.