KABUL, Afghanistan — Afghanistan released 65 accused militants from a former U.S. prison on Thursday despite protests from the American military, which says the men are Taliban fighters who will likely return to the battlefield to kill coalition and Afghan forces.

The move further strains relations between Washington and Afghan President Hamid Karzai, whose increasingly anti-American rhetoric and refusal to sign a long-negotiated bilateral security deal has heightened uncertainty ahead of the year-end withdrawal of most international combat troops.

Karzai ordered the detainees released several weeks ago, less than a year after his government took over the prison from U.S. troops.

The decision prompted angry denunciations from Washington. U.S. forces in Afghanistan say some of the men are responsible for killing or wounding dozens of international and Afghan soldiers, as well making bombs that have killed civilians.

The prisoners were freed just after 9 a.m. from the Parwan Detention Facility near the U.S. Bagram Air Field, about 28 miles north of Kabul, according to prison spokesman Maj. Nimatullah Khaki.

They were laughing and smiling as they boarded a bus to leave the facility, he said.

The U.S. had argued for the detainees to face trial in Afghan courts, citing strong evidence against them — from DNA linking them to roadside bombs to explosive residue on their clothing. However, Kabul cited insufficient proof to hold them.

Karzai has referred to the Parwan prison as a “Taliban-producing factory” where innocent Afghans have been tortured into hating their country. The president had long demanded that the U.S. turn over the prison to Afghan authorities, a process completed last March after lengthy negotiations — largely over American concerns that some of the most dangerous detainees would go free.

The U.S. military strongly condemned Thursday’s release, saying some of those set free were directly linked to attacks that have killed or wounded 32 U.S. or coalition personnel and 23 Afghan security personnel or civilians.

“They have killed Afghan men, women and children,” U.S. forces in Afghanistan said in a statement, adding that the coalition believes other alleged insurgents released from Parwan earlier “have already returned to the fight.”

A statement from the U.S. Embassy in Kabul on Thursday also condemned the release, saying the Afghan government “bears responsibility for the results” if those freed take up violence.

“We requested a thorough review of each case. Instead, the evidence against them was never seriously considered,” the embassy statement said.

Afghan Defense Ministry spokesman Mohammad Zahir Azimi would not comment on U.S concerns.

“Our responsibility is the protection of the prisoners. That is all,” Azimi said over the telephone.

The 65 were among 88 detainees at the facility that are the subject of dispute between Kabul and Washington. The U.S. says that they are dangerous members of the Taliban insurgency, the Haqqani group of militants and other Islamic radicals bent on fighting foreign and Afghan government forces.

Among those believed to have walked free Thursday morning was Mohammad Wali, who the U.S. military says is a suspected Taliban explosives expert who allegedly placed roadside bombs targeting Afghan and international forces. The military said Wali had been biometrically linked to two roadside explosions and had a latent fingerprint match on another improvised explosive device. He had also tested positive for explosives residue.

Others in the group include Nek Mohammad — who the U.S. says was captured with extensive weapons — and a man identified as Ehsanullah, who is claimed to have been biometrically matched to a roadside bomb and who tested positive for explosives residue.

The U.S. military had formally disputed the prisoners’ release, but an Afghan review board had overruled those challenges.

Some Afghans near the Parwan prison expressed unease over the release.

“I think they will return back to their people, to the Taliban,” said Ahmad Shayeq, whose home is near the facility.

The detainees’ release has been in the works for weeks, and comes as Karzai has taken an increasingly hostile tone toward the U.S.

The president has refused to sign a Bilateral Security Agreement that would allow a few thousand U.S. troops to remain in Afghanistan past 2014, largely to help train Afghanistan security forces to take over the fight against the Taliban 13 years after the military intervention in the wake of the Sept. 11, 2001 terror attacks in the U.S. The NATO-backed coalition toppled the Taliban regime of hard-line Islamic law for sheltering the al-Qaida leadership behind the U.S. attacks.

Karzai had tentatively endorsed the bilateral security deal, but after it was approved in November by a council of tribal elders known as the Loya Jirga, he refused to sign it — saying he wants his successor to decide about it after the April 5 presidential election. Karzai cannot run because he is ineligible to serve a third term.

The U.S. wants the deal signed as soon as possible because it needs time to prepare to keep thousands of U.S. troops in the country for up to a decade.