Heavily armed Congolese rebels taking refuge in their country’s Virunga National Park are placing endangered mountain gorillas under additional threat, according to conservation officials.

Africa’s most active volcano Nyamuragira, located in the Democratic Republic of Congo, erupted last weekend throwing off clouds of ash and orange smoke.

A Congolese environmental protection group said that DR Congo troops illegally killed animals last month in Virunga National Park, including seven hippos and five elephants.

The Virunga National Park, home to 200 of the world's 720 mountain gorillas, is in the path of molten hot lava spewing from a volcano that has erupted in the eastern Democratic Republic of Congo.

More than two years after being evacuated following the 2007 killings of their mothers, mountain gorilla babies Ndakasi and Ndeze this week returned home to the Democratic Republic of Congo, moving into a new custom-built forest sanctuary.