KANDAHAR  - Prison officials in Afghanistan's southern city of Kandahar have been tricked into releasing a dozen Taliban fighters, BBC reported Sunday.

The chief of security for Kandahar, Rahmatullah Atrafi, said a letter was sent to the prison on Tuesday requesting the release of 28 prisoners.

Sixteen were due for release but the other 12 were not. The deception was only discovered after the inmates had been freed. Officials say two have since been recaptured.

The search for the others continues. So far no group has said it was behind the deception although correspondents say the Taliban have carried out several jail breaks in recent years. Mr Atrafi said an investigation was being set up. "In this letter they added 12 prisoners, and that was fake," he said.

"A committee has been set up to look into the matter. In this delegation we have prison officials, prosecutors and security officials. "They are going to look into this and find out who was behind it. Whoever it is, they will be tried and punished."

The release of Taliban prisoners is a contentious issue in Afghanistan. In January, President Hamid Karzai's office said scores of prisoners previously held by US forces at Bagram jail would be released.

Washington expressed concern over the planned releases, saying it regarded them as "dangerous criminals".

Hundreds of prisoners at Bagram have been freed since the Afghan government took over the running of the prison in March 2013. Two of the 12 incorrectly released prisoners have been recaptured, BBC News says.

The Taliban claimed responsibility for the deceit. An investigation is being conducted to determine how the prisoners were incorrectly released. In January, Afghan President Hamid Karzai announced that many prisoners previously held by US forces in Bagram jail would be released, a decision that the US was heavily concerned by.