In claiming responsibility, the al-Qaida linked militant group cited anger at Pakistan's military for failing to stop the American incursion on their soil.
The blasts in the northwest were a reminder of the savagery of Islamist insurgents in Pakistan. Tensions also have risen between the U.S. and Islamabad over allegations that some elements of Pakistani security forces had been harboring bin Laden, who died in a May 2 raid in Abbottabad, a garrison town about three hours' drive from the scene of the bombing.
"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. He warned that the group was also planning attacks on Americans living inside Pakistan.
The bombers blew themselves up in Shabqadar at the main gate of the facility for the Frontier Constabulary, a poorly equipped but front-line force in the battle against al-Qaida and allied Islamist groups like the Pakistani Taliban close to the Afghan border. Like other branches of Pakistan's security forces, it has received U.S. funding to try to sharpen its skills.
At least 80 people were killed, including 66 recruits, and around 120 people were wounded, said police officer Liaqat Ali Khan.
Around 900 young men were leaving the center after spending six months of training there. They were in high spirits and looking forward to seeing their families, for which some had brought gifts, a survivor said.
Some people were sitting inside public minivans and others were loading luggage atop the vehicles when the bombers struck, witnesses said.
"We were heading toward a van when the first blast took place and we fell on the ground and then there was another blast," said 21-year-old Rehmanullah Khan. "We enjoyed our time together, all the good and bad weather and I cannot forget the cries of my friends before they died."
The scene was littered with shards of glass mixed with blood and flesh. The explosions destroyed at least 10 vans.
It was the first major militant attack in Pakistan since bin Laden's death on May 2, and the deadliest this year.
Militants had pledged to avenge the killing and launch reprisal strikes in Pakistan.
The Taliban spokesman suggested the attack was aimed as punishment against Pakistani authorities for failing to stop the unilateral U.S. raid that killed bin Laden, something that has sparked popular nationalist and Islamist anger.
"The Pakistani army has failed to protect its land," Ahsan said.
In its communications, the Taliban often tries to tap into popular sentiments in the country, where anti-Americanism is often stronger than feelings against Islamist militants. This is despite militant attacks over the last four years claiming the lives of many hundreds, if not thousands, of civilians.
Some 350 lawyers sympathetic with Islamists attended special prayers for bin Laden on the premises of the provincial high court in the eastern city of Lahore on Friday. The lawyers cursed the May 2 raid, chanting "Down with America."
The explosive vests used in Friday's attacks were packed with ball bearings and nails, police said.
Police official Nisar Khan said a suicide bomber in his late teens or early 20s set off one of the blasts.
"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.
Bin Laden, the Sept. 11 mastermind, and at least four others were killed by U.S. Navy SEALs who raided his compound in Abbottabad. 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 criticized the U.S. raid ordered by President Barack Obama as a violation of their country's sovereignty. To counter allegations that Pakistan harbored bin Laden, the officials point out that thousands of Pakistani citizens, and up to 3,000 of its security forces, 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 have targeted Pakistani security forces, but government buildings, religious minorities and Western targets also have been hit.
Pakistan's intelligence chief, Gen. Ahmed Shuja Pasha, admitted "negligence" on the part of authorities in failing to find bin Laden during a closed session in Parliament on Friday, a government spokeswoman told reporters. Military officials, including the powerful army chief Gen. Ashfaq Parvez Kayani, said they would improve the country's air defenses, which did not detect the high-tech U.S. choppers used in the raid.
The military leaders also assured lawmakers that Pakistan's nuclear arsenals are safe and that the armed forces were capable of defending the country, said Firdous Ashiq Awan, the federal information minister.
In another development Friday, Pakistani intelligence officials said a U.S. missile strike killed three people near the Afghan border.
The four missiles struck a vehicle in the Doga Madakhel village of North Waziristan tribal region. North Waziristan is home to many militant groups dedicated to attacking Western troops in Afghanistan.
The two officials spoke on condition of anonymity because they were not authorized to speak to media. They did not know the identities of the dead.
Also in the northwest Friday, some two dozen vehicles, including 15 tankers carrying fuel for NATO in Afghanistan, were destroyed when a blast ripped through a parking lot in Pakistan's Khyber tribal region, government official Tahir Khan said.
The U.S. and NATO rely heavily on Pakistani land routes to transport large amounts of non-lethal supplies into Afghanistan. Militants and ordinary criminals have often attacked the supply line, but NATO and the U.S. say the attacks have not impacted the war effort. Still, the military alliance is increasingly using other roads into Afghanistan, including those coming from Central Asia.
Associated Press writers Ashraf Khan and Deb Riechmann in Islamabad, Babar Dogar in Lahore and Ishtiaq Mahsud in Dera Ismail Khan contributed to this report.