Prison officials in Afghanistan's southern city of Kandahar have been tricked into releasing 12 Taliban fighters.

The chief of security for Kandahar, Rahmatullah Atrafi, said a letter had been sent to the prison on Tuesday requesting a prisoner release.

Eighteen inmates on the list were due to be freed, but the other 12 were not.

The Taliban say they carried out the deception, which was only discovered after the inmates were freed.

Officials say two have since been recaptured. The search for the others continues.

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.

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.