SHABQADAR, Pakistan >> Twin explosions struck a paramilitary training center in northwestern Pakistan on Friday, killing at least 69 people, in an attack that the Pakistani Taliban claimed it carried out to avenge the killing of 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.

Most of the dead were recruits.

The scene of the blast was littered with shards of glass mixed with blood and human flesh. The explosions destroyed at least 10 vans the recruits were boarding to go home for a short break at the end of a recent training session.

Regional police officer Liaqat Ali Khan said at least 69 people died in the attack. Dr. Abdul Hameed Afridi of Lady Rieding Hospital in Peshawar said 117 people have been treated at the hospital, including 40 with critical wounds.

It was the bloodiest attack in Pakistan since bin Laden’s death in a May 2 U.S. raid in the city of Abbottabad.

Militants had pledged to avenge the killing and launch reprisal strikes in Pakistan.

“We have done this to avenge the Abbottabad incident,” Ahsanullah Ahsan, a spokesman for the Pakistani Taliban, told The Associated Press in a phone call. “Also, the Pakistani army has failed to protect its land.”

About 3 to 4 pounds (6 to 8 kilograms) of explosives were used in one explosion, said police officer Jahanzeb Khan. Ball bearings and nails were used in another, heightening the death toll, he said.

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.”

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.

Police official Nisar Khan said a suicide bomber in his late teens or early 20s set off one of the blasts. The cause of the other explosion was not yet known, he said.

“The first blast occurred in the middle of the road, and after that there was a huge blast that was more powerful than the first,” said Abdul Wahid, a 25-year-old recruit whose legs were wounded in the blasts.

He said he was knocked to the ground by the force of the explosions.

“After falling, I just started crawling and dragging myself to a safer place … along the wall of a roadside shop,” he said.

The Sept. 11 mastermind and at least four others were killed by U.S. Navy SEALs who raided bin Laden’s compound in Abbottabad, a garrison city not far from the capital. Bin Laden is believed to have lived in the large house for up to six years.

Pakistani officials have denied knowing he was there but have criticized the American raid ordered by President Barack Obama as a violation of their country’s sovereignty.

Pakistani leaders have repeatedly pointed out that tens of thousands of their own citizens have died in suicide and other attacks since Sept. 11, 2001, when Islamabad became an ally of the U.S. in taking on Islamist extremists. Many of the attacks in Pakistan have targeted security forces, including young cadets or recruits.