A volcano erupted near the city of Goma in eastern Congo, spewing lava in an area devastated by a major eruption four years ago.
Mount Nyamulagira began erupting at about 10 p.m. (2000 GMT) Monday, said Celestin Kasereka, head of the Goma volcano observatory.
A red glow suggested that lava fountains and flows appeared to be continuing Tuesday, said Jacques Durieux, the U.N. manager for the observatory. But he said the team did not yet have a sense of the size or seriousness of the eruption.
He said observers are trying to get a U.N. helicopter to fly over the area. He said the area around the volcano is largely uninhabited. "We aren't on the ground because of security reasons," Durieux said.
The area around Goma has seen days of clashes between forces loyal to a dissident former general and Congo's army that have killed at least three people. U.N. forces were drawn into the unrest on Monday.
Goma a provincial capital of about 500,000 people is not in the path of lava flows from Nyamulagira because its sister volcano, Mount Nyirangongo, protects the city.
"Nyirangongo constitutes a barrier," Kasereka said. Nyirangongo is about 20 kilometer (13 miles) northeast of Goma, while Nyamulagira is another 16 kilometers (10 miles) further to the northeast. They are the only two active volcanoes in the region.
In 2002, the eruption of Nyirangongo destroyed about a fifth of the residential areas of Goma, the provincial capital of Congo's North Kivu province. About 100 people died as lava flows as deep as 3 meters (10 feet) overtook parts of the city, reports AP.
Nyamulagira erupted later the same year, spewing plumes of lava 90 meters (300 feet) into the air, but without threatening Goma.
Nyamulagira erupts every year or two, but rarely affects populated areas.
The fighting has been centered around the town of Sake, about 30 kilometers (18 miles) west of Goma in the opposite direction from the volcanoes.
Largely lawless eastern Congo has been home to numerous rebellions in recent years as rival warlords claim swaths of land some hanging on despite recent elections designed to unify the country under democratic rule.