Afghanistan will release scores of prisoners considered by the US to be a security threat because there is insufficient evidence against them, President Hamid Karzai’s office says.

A statement said there was not enough evidence against 72 out of 88 prisoners previously held by the US.

Correspondents say that the move will further strain relations with the US.

The two countries are at loggerheads over President Karzai’s refusal to sign a security deal with Washington.

The US is strongly opposed to the releases because it says the prisoners have been involved in the wounding or killing of US and Nato troops.

Hundreds of prisoners from Bagram jail have been freed since Kabul took over the running of the prison in March 2013.

The Afghan government says that there is no evidence against 45 out of 88 prisoners, while the evidence against a further 27 detainees is not enough to put them on trial.

Read more at BBC News