"Without getting into hypotheticals, every day we continue to go after those enemies in Afghanistan that are targeting our forces, the forces of our allies and the Afghan people, and nothing's going to change about that. And should one of these detainees rejoin the fight, they need to know that they do it at their own peril," said the Pentagon's press secretary, Navy Rear Adm. John Kirby.
The 65 were released Thursday by the Afghan government over strenuous objections by the U.S. government, which says the men are dangerous Taliban fighters and bomb-makers likely to return to killing foreign forces and Afghans.
Kirby said the 65 are not considered targets at the moment.
"There's not going to be an active targeting campaign, if that's what you're asking for, to go after them," Kirby said. "That said, if they choose to return to the fight, they become legitimate enemies and legitimate targets."
The U.S. has asserted that some of them were directly linked to attacks that have killed or wounded 32 U.S. or coalition personnel and 23 Afghan security personnel or civilians.
"All of these individuals are people who should not be walking the streets," Kirby said. "And we had strong evidence on all of them -- evidence that has been ignored. And that's unsatisfactory to us."
Kirby said Washington is concerned that the government of President Hamid Karzai might release additional prisoners deemed by the U.S. to be dangerous.
The spokesman said Defense Secretary Chuck Hagel is frustrated by a number of recent moves by Karzai, including his decision to release the 65 prisoners.
The Obama administration also has been aggravated by Karzai's refusal to sign a long-term security agreement with the U.S. that he agreed to last year. The pact would provide the legal basis for any U.S. forces to remain in Afghanistan as trainers and advisers after the international combat mission ends in December.
"This is a relationship that matters and a country that matters. And as frustrating as it can be at times, he (Hagel) also believes we need to keep working at this," Kirby said.