NATO forces in Afghanistan have stopped handing over prisoners to some Afghan jails after an unpublished United Nations report detailed allegations of torture in the prisons.

Coalition officials said Wednesday they are proceeding with “appropriate caution” and suspending detainee transfers to certain facilities until the details of the pending U.N. report are verified. The United Nations Assistance Mission in Afghanistan says the report is in the final stages of completion.

Authorities reportedly are focused on at least eight Afghan jails where alleged incidents of torture have occurred.

Afghanistan's Interior Minister Bismillah Mohammadi and intelligence chief Rahmatullah Nabil have rejected the allegations and questioned the timing of the decision, which comes as international forces are transitioning security responsibilities to the Afghan government.

UNAMA spokesman Dan McNorton would not detail the allegations, but said the findings indicate that the mistreatment of detainees is not institutional or government policy in Afghanistan. He says the Afghan government is taking the findings extremely seriously and proposing a series of remedial actions.

Some analysts fear that concerns over torture will call into question how ready the Afghans are to take over the lead role in security operations from the coalition forces.

NATO is in the first phase of handing security over to Afghanistan's army and police in a gradual process due to be completed in approximately three years.