A UN report states that prisoners in Afghan custody were threatend with sexual assualt and electric shock [Reuters]

The US-led coalition in Afghanistan has suspended its transfer of detainees to Afghan prisons following allegations by the UN that prisoners are being tortured.

The allegations were leaked on Tuesday ahead of a UN report that claims prisoners have been beaten with rubber hoses, threatened with sexual assault and given electric shocks.

A NATO official said that transfers have been suspended pending an investigation by the International Security and Assistance Force (ISAF).

The suspension affects detention centres run by the Afghan police and intelligence service in Herat, Khost, Lagman, Kapisa and Takhar.

Dan McNorton, a spokesman for the United Nations Assistance Mission in Afghanistan (UNAMA) told Al Jazeera that it shared its findings with the Afghan government, including the national directorate of security. 

"We understand they are taking the findings very seriously and are proposing a series of remedial actions,"  McNorton said.

"Our findings indicate that the mistreatment of detainees is not an institutional or government policy of the Government of Afghanistan."

Speaking to Al Jazeera, Professor Scott Horton of Columbia Law School described the allegations as "a major complication" to NATO's plans to wind down its presence in Afghanistan.

"The NATO nations are members of the convention against torture," he said. "Article III requires that if they  have reason to believe that a person if turned over to another government would be tortured, they're not permitted to turn them over. So the decision that was taken today is exactly what is required of them."

"I think, inevitably, it will slow [the withdrawal of forces] down unless this could be corrected," Horton added.