A fifth rare mountain gorilla has been found shot dead inside the Virunga National Park in eastern Democratic Republic of Congo. In an unusual attack last month the five endangered animals were killed and their carcasses left in the park and not eaten or sold. Kari Barber has more from VOA's West and Central Africa bureau in Dakar.

The remains of a female mountain gorilla were discovered Thursday near a ranger station in the city of Goma. Nine mountain gorillas have been killed this year in the region. In the past, the endangered primates have been killed for their meat by rebel groups who occupy the forests or to be sold by poachers.

Samantha Newport of the conservation group WildlifeDirect says what is unusual about the recent killings is that no meat was taken and and a baby gorilla was left behind.

"In the recent cases, they have been killed execution style almost, with bullets to the head or the back of the neck. There is also evidence during the recent massacre that machetes were used," said Newport.

Newport says one male gorilla escaped with a cut on his arm from a machete.

About 100 of the world's approximately 700 remaining mountain gorillas live in Virunga National Park.

Newport says the gorilla family whose members were killed in July are starting to recover from their loss and behave normally. But, she says, they have no females left in the family to reproduce with, hampering conservationists' efforts to protect the species from extinction.

The Virunga National Park is situated in an unstable region of the DRC which is occupied by the Congolese army, dissident members of the army, Rwanda refugees, and various Mai Mai rebel groups.

"They live in one of the most dangerous areas of the world that has seen armed conflict for the last 10 to 12 years. They are really under considerable pressure from encroaching populations, militia groups and poachers," added Newport.

Rangers say the trees in the forest where the gorillas live are a source of charcoal, and the killings may be linked to a struggle for power between those who want to protect the forrest and those involved in illicit trade. Newport says this link is being investigated.

Newport says wildlife groups have stepped up efforts to protect the gorillas.

"There is action that is taking place to reinforce the presence of the guard in the park and provide around-the-clock monitoring of the gorilla family," said Newport.

She says for rangers, defending the gorillas is a difficult task since would-be poachers and assailants are armed and often very dangerous.

Virunga National Park is Africa's oldest national park and used to be a major tourist attraction before war destabilized the region in the 1990's.