Rebels attacked a United Nations peacekeeping base in eastern Congo, killing at least 14 peacekeepers and wounding 40 others in the worst violence against the mission in this Central African country in years.

Deputy spokesman Farhan Haq in New York said the peacekeepers were mainly from Tanzania, and that at least five Congolese soldiers also were killed in the assault blamed on one of the region's deadliest rebel groups.

"It's a very huge attack, certainly the worst in recent memory," Haq said.

The peacekeeping base is located about 45 kilometres (27 miles) from the town of Beni, which has been repeatedly hit by rebels from the Allied Democratic Forces rebel group.

The base is home to the peacekeeping mission's rapid intervention force, which has a rare mandate to go on the offensive, according to Radio Okapi, which is backed by the US mission.

The radio station, citing military sources, said fighting lasted four hours.

Nearly 300 peacekeepers have been killed since the UN mission arrived in 1999, according to UN peacekeeping data.

Congo, a country the size of Western Europe, has seen immeasurable cruelty and greed as a result of its vast mineral resources. The nation suffered through one of the most brutal colonial reigns ever known before undergoing decades of corrupt dictatorship. Back-to-back civil wars later drew in a number of neighboring countries.