KANDAHAR, Afghanistan (AP) — During the long Afghan winter, Taliban insurgents were apparently busy underground.

The militants say they spent more than five months building a 1,050-foot tunnel to the main prison in southern Afghanistan, bypassing government checkpoints, watch towers and concrete barriers topped with razor wire.

The diggers finally poked through Sunday and spent 4 1/2 hours ferrying away more than 480 inmates without a shot being fired, according to the Taliban and Afghan officials. Most of the prisoners were Taliban militants.

Accounts of the extraordinary prison break, carried out in the dead of night, suggest collusion with prison guards, officials or both.

Following a recent wave of assassinations here, the breakout underscores the weakness of the Afghan government in the south despite an influx of international troops, funding and advisers. It also highlights the spirit and resourcefulness of the Taliban despite months of battlefield setbacks.

Officials at Sarposa prison in Kandahar city, the one-time Taliban capital, say they discovered the breach at about 4 am yesterday, a half-hour after the Taliban say they had gotten all the prisoners safely to a house at the other end of the tunnel.

Government officials corroborated parts of the Taliban account. They confirmed the tunnel was dug from a house within shooting distance of the prison and that the inmates had somehow gotten out of their locked cells and disappeared into the night. Kandahar remains relatively warm even during winter and the ground would not have frozen while insurgents were digging the tunnel.

Police showed reporters the roughly hewn hole that was punched through the cement floor of the prison cell. The opening was about 3 feet , and the tunnel dropped straight down for about 5 feet and then turned in the direction of the house where it originated.

But access was denied to the tunnel itself, and it was unclear how the Taliban were able to move so many men out of the prison so quickly. Also unclear was why guards would not have heard the diggers punch through the cement floor, and whether they supervise the inside of the perimeters at night.

A man who claimed he helped organize those inside the prison told The Associated Press in a phone call that he and his accomplices obtained copies of the keys for the cells ahead of time from “friends.” He did not say who those friends were.

“There were four or five of us who knew that our friends were digging a tunnel from the outside,” said Mohammad Abdullah, who said he had been in Sarposa prison for two years after being captured in nearby Zhari district with a stockpile of weapons. “Some of our friends helped us by providing copies of the keys. When the time came at night, we managed to open the doors for friends who were in other rooms.”

He said the diggers broke through Sunday morning and that the inmates in the cell covered the hole with a prayer rug until the middle of the night, when they started quietly opening the doors of cells and ushering prisoners in small groups into the tunnel.

He said they woke the inmates up four or five at a time to sneak them out quietly. They also didn’t want too many people crawling through the narrow and damp tunnel at one time because of worries that they would run out of oxygen, Abdullah said.

The AP reached Abdullah on a phone number supplied by a Taliban spokesman. His account could not immediately be verified.

The Taliban statement said it took 4 1/2 hours for all the prisoners to clear the tunnel, with the final inmates emerging into the house at 3:30 am They then used a number of vehicles to shuttle the escaped convicts to secure locations.

Reporters were not allowed into that building, but officials pointed out the mud-walled compound with a brown gate and shops on either side.

The city’s police mounted a massive search operation for the escaped convicts. They shot and killed two inmates who tried to evade capture and re-arrested another 26, said Tooryalai Wesa, the provincial governor.

But there was no ignoring that the Taliban had pulled off a daring success under the noses of Afghan and NATO officials.