Afghan President Hamid Karzai (Rahmat Gul/AP Photo)

In another low point in Afghanistan's relationship with the United States, Afghanistan has released 65 detainees that the U.S. military says are among the most dangerous men in the country.

Afghanistan went through with the release over the objections of U.S. and NATO officials who say the men were directly implicated in deadly attacks that killed or wounded 32 American and coalition service members.

In the months leading up to today's release, U.S. officials have launched a public campaign urging Afghanistan not to release the detainees, who are among the final 88 detainees once under U.S. control. They have said there is enough evidence for Afghan officials to proceed with their prosecution instead of their release.

Afghan President Hamid Karzai has steadfastly defended the independence of those Afghan officials to review the cases. The Afghan panel that has been reviewing the cases has released more than 500 of the 700 detainees that were transferred to Afghan control.

"Afghanistan is a sovereign country," said Karzai today. "If Afghan judicial authorities decide to release a prisoner, it is of no concern to the U.S."

NATO Secretary General Anders Fogh Rasmussen said he was "gravely concerned" by the release, which he said seemed to have been "based on political calculations and without regard for due process before the Afghan courts."

A statement from U.S. Forces -Afghanistan said the release "poses a threat to U.S., Coalition and Afghan National Security Forces, as well as the Afghan population. Insurgents in the group released today have killed Coalition and Afghan Forces."

Some American officials have speculated that Karzai has backed the detainees' release as part of an effort to work out a separate peace deal with the Taliban.

Karzai has also refused to sign a bilateral security agreement with the United States that would enable the Obama administration to keep U.S. military training forces in Afghanistan after this year. Karzai said he will let his successor deal with the agreement after Afghanistan's presidential elections in April.

A U.S. official said that some of the 65 detainees released today were directly linked to attacks that killed or wounded 32 U.S. or coalition personnel, and also killed 23 Afghan troops and civilians. Of the 65, 25 of them were allegedly linked to the making and placing of roadside bombs and 33 of them tested positive for explosive residue on their person after they were captured, the U.S. official said.

Following the release, the BBC interviewed a small group of detainees who had gone to a Kabul café for lunch.

One of those men, Nurullah, is accused by U.S. authorities of being responsible for a Taliban attack that killed an American soldier and wounded four others.

Nurullah denied involvement in the attack and said he had been training as a builder. "I have no link with any groups," Nurullah told the BBC.

A U.S. official said that when Nurullah was apprehended almost a year ago he was "captured with an RPG launcher, rifle, shotgun, grenade, RPG boosters, ammunition, 60 mm mortar system, and military explosives."

Another released detainee is alleged to have been involved in the August 16, 2012, downing of a Blackhawk helicopter in southern Afghanistan that killed seven American service members and four Afghans.

The U.S. official described Haji Abdullah as the leader of a Taliban cell who enabled bomb attacks on ISAF and Afghan forces in Kandahar Province and had claimed partial responsibility for the helicopter attack.

The official said he had allegedly sheltered and escorted the triggerman who fired two rocket propelled grenades that brought down the aircraft.