KABUL, Afghanistan — Afghanistan released 65 accused militants from a former U.S. prison today 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 from a detention facility near the U.S. Bagram Air Field, 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.

The U.S. military strongly condemned the 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.