KANDAHAR, Afghanistan — The Taliban staged an audacious prison break here early Monday, freeing at least 476 political prisoners through a long tunnel, according to the warden, Gen. Ghulam Dastagir Mayar.

He said that security authorities had discovered in the morning that the prisoners from the political wing of the building were gone, and that the authorities had just found the tunnel. “We do not know if the tunnel was dug from outside or inside the prison,” he said.

The Kandahar prison is the largest and most substantial prison in southern Afghanistan, and it houses Taliban who were captured in Zabul, Oruzgan and Kandahar, including some senior Taliban figures as well as many lower level Taliban, according to security officers working with the prison.

It was the second time there has been a major prison break at the Sariposa prison in Kandahar. The Taliban orchestrated the freeing of 1,200 prisoners, of whom 350 were Taliban members, on June 13, 2008, staging an attack on the prison that killed 15 guards.