The U.S. military says Afghanistan's government has released 37 "dangerous" prisoners who pose threats to the country and the region.

The release of prisoners has been a sticking point in Afghan-U.S. relations as the two sides struggle over a deal allowing U.S. and allied troops to remain in the country past the end of this year.

The U.S. on Monday condemned the release of "dangerous insurgents who have Afghan blood on their hands," linking them to roadside bombings and attacks on foreign and government troops.

The Afghan government has said a review of the prisoners' cases turned up no evidence of wrongdoing for 45 of 88 detainees the U.S. wants held, and that there was insufficient evidence on the others.

Afghan officials did not return repeated calls for comment Monday.