The United States is quietly keeping non-Afghan detainees in custody at Bagram prison in Afghanistan, despite turning the prison over to Afghan control last year, according to a new report issued by the nonprofit Justice Project Pakistan (JPP).

In its report "Closing Bagram: The Other Guantanamo," the organization details what it calls the failure of the U.S. to resolve the cases of its numerous detainees at the prison, many of whom are Pakistani.

According to JPP, some of the detainees have actually been cleared for release but are stuck in legal limbo because the U.S. hasn't been able to negotiate their release or send them back to their home country.

Bagram prison has been the source of much controversy. Now in operation for more than 10 years, it is referred to by some as Afghanistan's "Guantanamo" because of numerous allegations of serious prisoner abuse by U.S. soldiers.

There are more than 3,000 prisoners held there, and an additional 600 have been detained since control of the prison was handed over to the Afghan government in March 2012. About 50 of those under U.S. custody are Pakistani foriegn nationals, according to Al Jazeera.

In a press release, JPP implored the U.S. to take action to end the detainees' indefinite detention before the scheduled 2014 troop withdrawal.

"Truly bringing an end to the U.S. war in Afghanistan means releasing or repatriating detainees that it is still holding there," said Sarah Belal, director of JPP. "The United States must make sure it does not repeat the mistakes and injustices of the past, and that Bagram does not follow Guantanamo's tragic path."

Elissa Smith, a U.S. Defense Department spokesman, told Al Jazeera in an e-mail that all detainees currently held by the U.S. are being held lawfully and that there is an ongoing review process being used to determine if those in custody present a security threat to the U.S.

"The U.S. remains committed to seeing that every detainee held by our forces who can be transferred to a verifiably secure and humane situation, is, and that no one is held unnecessarily for any period longer than necessary," Smith wrote. "No one wants to be a detainee. So, of course the stories relayed by detainees to a sympathetic NGO reflect all manner of claims that simply are not supported when real, intellectual rigor is applied."

JPP is calling on the U.S. to publicly commit to end detentions at Bagram by 2014, grant the detainees access to legal counsel and negotiate a comprehensive agreement that will repatriate Pakistani detainees.

"These individuals are trapped in indefinite, illegal detention," said Belal in the press release. "The U.S. and other governments have the means to bring this to an end -- it is time that they and the public have the will."

Al Jazeera