Twin explosions struck a paramilitary training center in northwestern Pakistan on Friday, killing at least 68 people _ nearly all recruits _ in the bloodiest attack in the country since a U.S. raid killed al-Qaida chief Osama bin Laden.

A suicide bomber detonated at least one of the blasts at the main gate of the facility for the Frontier Constabulary, a poorly equipped but front-line force in Pakistan's battle against al-Qaida and allied Islamist groups close to the Afghan border. Like other branches of Pakistan security forces, it has received U.S. funding.

The attack was a savage reminder of the toll militant groups are taking on Pakistan even as it faces international suspicion that elements within its security forces may have been harboring bin Laden, who was killed in a raid about three hours' drive from Peshawar.

Dozens of people also were wounded, said police official Nisar Khan. He said a suicide bomber, a man in his late teens or early 20s, set off one blast. The cause of the other explosion was not yet known, he said.

Many recruits were boarding vehicles to go home for a short break at the end of a recent training session.

A vegetable vendor at the site said some recruits were seated in white minivans and others were loading luggage atop the vehicles.

``There was a big blast,'' he said. ``I saw smoke, blood and body pieces all around.''

(AP)