It's a big eruption, there's a fountain of lava 100 metres high

Vulcanologist Dieudonne Wafula

Local vulcanologist Dieudonne Wafula said ash and debris were being thrown high above the crater and lava was flowing down both sides of the volcano, the 3,000 metre high Mount Nyamuragira.

However, he said there was no direct threat to the local population.

"There's a lava flow to the north and to the south... It's a big eruption, there's a fountain of lava 100 metres (300 feet) high, ash and volcanic debris in the air," he told Reuters news agency.

He said the lava was flowing through the largely uninhabited Virunga Park, though falling ash could destroy fields as far as 20 km from the volcano.

BBC Kinshasa correspondent Mark Dummet says there are no formal settlements in Virunga Park, but throughout the four-year Congolese war, it has been used as a hideout by Rwandan militias responsible for the 1994 genocide.

Goma calm

In January, a major eruption at nearby Mount Nyiragongo destroyed parts of Goma, forcing tens of thousands of people to flee temporarily into neighbouring Rwanda.

A plume of smoke has been reported to be rising from Nyaragongo and a UN assessment team is preparing to survey both volcanoes by helicopter.

Aloys Badege, a journalist with Radio Rwanda, told Reuters there was no panic in Goma itself.

"It's just erupting towards the forest, it's not near Goma," he said.

Local government officials told AFP news agency that Nyamuragira erupted late on Thursday from a fissure on its western flank.

The lava is reported to be flowing towards three villages: Rutshuru, Rumangabo and Sake.

Nyamuragira last erupted in February last year.

Nyiragongo and Nyamulagira are the only two active volcanoes in the region.