Rebels attacked a United Nations peacekeeping base in eastern Congo, killing at least 14 peacekeepers and wounding 53 others in the worst single attack against a U.N. mission in recent history, officials said Friday.

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 a rebel group based in neighboring Uganda.

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

The peacekeeping base is located about 45 kilometers (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 U.N. mission.

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

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.

The conflicts have been numerous since the U.N. mission's arrival in 1999. Many rebel groups have come and gone, at times invading the regional capital, Goma. One of the greatest threats in the region now comes from the ADF. Human rights groups say its fighters have killed about 1,000 people in the past three years.

The U.N. mission in 2006 helped carry out Congo's first free and fair elections in 46 years, but since then the winner of that vote, President Joseph Kabila, has become further entrenched in his post. Anger has grown as presidential elections originally set for late last year have been repeatedly delayed.