(Previous dateline Washington, adds comments by U.S ambassador)
WASHINGTON/KABUL, Jan 27 (Reuters) - The United States warned the Afghan government on Monday against releasing prisoners that Washington says should be tried as dangerous militants, the latest dispute to inflame U.S.-Afghan relations.
Colonel Steve Warren, a Pentagon spokesman, said the Afghan government had directed the Afghan Review Board, a government body, to release 37 detainees.
Warren said some were linked to production of improvised bombs or attacks using them, while others were believed to have been involved in assaults on Afghan or foreign soldiers
"These are bad guys. These are individuals with blood on their hands, both U.S., coalition and Afghan blood on their hands," Warren told reporters.
The prisoners, he said, were "in the release process" despite "strong evidence" that would support prosecution of some prisoners and leads on other prisoners that justified further investigation.
The detainees are among 650 held at Bagram prison north of Kabul which Afghan authorities have marked for release on grounds of insufficient proof to prosecute them. Washington objects to freeing a total of 88 prisoners it regards as a threat to security.
The dispute over the prisoners is one of a series of incidents marking a deterioration in ties.
President Hamid Karzai has refused to sign a security pact that would enable U.S. troops, in the country since 2001, to remain beyond the end of the year. He says the accord can wait until after a presidential election in April.
U.S. ambassador James Cunningham said he hoped relations could be repaired quickly as most foreign troops prepare to leave, and as Afghanistan prepares for an April presidential election.
"I would hope that we can get back to relationship that's based on fact," Cunningham told reporters in Kabul late on Monday. "We've had strong disagreements and we've always found a way to deal with them."
"The reality is the security transition. Whether we sign an agreement that cements our security cooperation and the elections - and those are coming up in the next couple of months - and we need to find a way to deal with that."
He said "facts had been distorted" in the row over the detainees and in a separate dispute over conflicting accounts of civilian casualties in an air strike by foreign forces on a village this month.
Afghan officials say all but 16 of the 88 prisoners raising objections in Washington will be released.
Karzai's spokesman said the U.S. attempt to block the release was a clear breach of Afghan sovereignty."
"The release of innocent Afghan detainees from Bagram prison is the decision of our judicial authorities ... it has to be respected and put in action as soon as possible," the spokesman, Aimal Faizi, told Reuters on Monday. (Reporting By David Alexander, Missy Ryan and Doina Chiacu in Washington and Jessica Donati in Kabul; Editing by Grant McCool, David Gregorio and Ron Popeski)