KINSHASA, Nov 27 (Reuters) - A volcano erupted on Monday near the eastern Congolese town of Goma, which was devastated by a volcanic eruption in 2002, but the latest eruption did not threaten the town, a senior vulcanologist at the scene said.

"This seems like a big eruption. It is on the northwest side. The lava will be flowing to the north and not the south, where the town is," Celestin Kasereka, head of Goma's volcano observatory, told Reuters by telephone.

Kasereka said the Nyamulagira volcano had begun to erupt at around 2000 GMT on Monday. Any lava flow would likely affect the Virunga national park, he said.

The Nyamulagira volcano erupted in July 2002, spewing lava 200 metres (600 feet) into the air.

The larger, neighbouring Nyiragongo volcano erupted in January 2002, pouring lava over much of Goma, sending hundreds of thousands of people fleeing for their lives, and compounding the misery of the border city then caught in the midst of a regional African war.

Kasereka and international peacekeepers stationed in the area said they could see a red glow reflected off the sky above the volcano.

"We will have to talk to the U.N. because we can't go and have a look yet due to the security situation," Kasereka said.

At least five people have been killed and dozens more injured since Saturday when soldiers loyal to a renegade general seized the town of Sake, just 20 km (13 miles) from Goma.

U.N. ground forces and helicopter gunships went into action against the rebels on Monday to prevent them advancing on the town.