President Hamid Karzai of Afghanistan is describing the escape of 476 political prisoners, including 100 Taliban commanders, as a disaster.
Insurgents rented a house, then spent five months digging a tunnel directly into the main jail in Kandahar. The tunnel was 320 metres long.
The provincial governor's office said at least 12 have since been recaptured.
Mr Karzai's office said the escape should never have happened and the government is looking for answers. The prison is under Afghan control.
The breakout was the second major escape in three years. In June 2008 a suicide bomber blew open the prison gates and about 900 prisoners fled.