A fierce gunbattle broke out between security forces and a team of Taliban fighters targeting U.N. and government buildings Friday in a major city in southern Afghanistan.

The fighting in Lashkar Gah came nearly two weeks after a similar assault in the Afghan capital, once again showing the ability of insurgents to penetrate heavily secured areas.

Taliban spokesman Qari Yousef Ahmadi said seven men armed with suicide vests and machine guns attacked the U.N. office and a guesthouse used by government officials in Lashkar Gah, capital of volatile Helmand province.

Afghan police and soldiers had five or six would-be suicide bombers trapped on top of a building under construction in a neighborhood housing the local branch of the U.N. Assistance Mission in Afghanistan and government buildings, according to officials.

Witnesses said attack helicopters were firing on the building.

An official with the counterterrorism department, who goes by the single name Almas, said a man who was passing by when the fighting began was killed.