— So much had changed in the three years since the Taliban blew up the barrier wall at Sarposa prison and sprung 900 inmates: imposing rows of concrete walls backed by razor wire, floodlights, video cameras, sand bags and 40 well-armed American soldiers watching from perimeter guard towers with Afghan police.

Kandahar’s largest detention facility had become so secure, said an American military officer giving a tour of the prison this year, that the only way to break through was to “put a nuke on a motorcycle.”

Or to dig more than 1,000 feet of underground tunnels and pop up into the middle of the prison, as the Taliban did early Monday, freeing one-third of the inmates and collapsing months of efforts to improve security at the jail. The audacious prison break showed again the vulnerabilities in Afghanistan’s justice system, despite rigorous U.S. oversight and a growing sense that authorities had the problematic prison under control.

The Taliban this month has penetrated some of Afghanistan’s most aggressively defended facilities. Attackers have killed Kandahar’s police chief inside his headquarters, exploded on a crowded Afghan army base in Laghman province, and shot up the hallways of the Ministry of Defense in Kabul. The security breaches have raised concerns about the Afghan government’s ability to protect itself from insurgents as U.S. and NATO forces begin to withdraw.

“This clearly shows the weakness of the government and the security forces, and if this doesn’t change, the prison breaks will happen again and again,” said Agha Lalai Dastageri, a provincial councilman in Kandahar.

The jailbreak occurred just as the traditional fighting season gets under way in Afghanistan, and in a part of the country where the U.S. military has focused its efforts. The Taliban movement began in southern Afghanistan, and over the past year U.S. forces have pushed the group out of several areas where it had established dominance earlier in the war. Although U.S. and Afghan soldiers have made progress in the south, most of the violence they face remains in Kandahar and Helmand. 

The escaped prisoners probably included members of the Taliban. Inmates in Sarposa are generally those detained by Afghan security forces but can include senior insurgents. A U.S. military spokesman in Kabul referred questions about the jailbreak to Afghan authorities, who are responsible for the prison. 

The prison break occurred before dawn Monday, but work on the tunnel had been going on for months, said Taliban spokesman Zabiullah Mujahid. There were conflicting reports on the tunnel’s length: The Taliban said it was about 1,200 feet long; Gen. Ghulam Dastagir Mayar, the prison warden, said it ran about 4,000 feet from the southwestern corner of the complex.

The tunnelers reached the surface inside the “political wing” of the prison and ushered out the detainees before dawn. Mayar said the security guards were not asleep but blamed the breach on an undermanned staff. “We cannot put security guards in every room,” he said. 

A second branch of the tunnel went to another part of the prison, but Afghan authorities found it and were able to prevent an exodus from that section, Kandahar governor Toryalai Wesa told reporters. When authorities followed the tunnel, they arrived at a house where they found explosives, an Afghan army commander said at the news conference.

Wesa said that 24 of the 480 escaped prisoners had been recaptured alive and that two had been killed. If more were found, Wesa said, identifying them would be easier because the prisoners had been registered in a biometric database. During recent visits by The Washington Post to the prison complex, U.S. military officials said they had not completed the biometric registry of all prisoners.

Judicial ‘green zone’

American troops have spent months trying to improve the physical security and the judicial proceedings at Sarposa. During the June 2008 attack, a car bomb exploded along the perimeter wall, killing several people and allowing an exodus from the prison. The hole in the wall has been patched, and layers of new barriers were constructed.

Since the fall, workers have have been building a “rule of law” complex adjacent to the prison, intended as a gathering place for prosecutors and judges to conduct investigations and trials. The goal has been to establish a secure environment for Afghanistan’s fledgling legal system to take root — and provide a legitimate alternative to the swift if brutal form of justice meted out by the Taliban.

The U.S. military’s Task Force 435, which oversees detainee issues, has two advisers at the site, along with about 40 U.S. soldiers from a military police battalion. The State Department’s bureau of international narcotics and law enforcement affairs has been planning to fund 45 advisers to work at the prison compound.

When completed, the complex, sometimes referred to as a judicial “green zone,” would have dorm rooms for guards, so they do not have to risk sleeping at home. There are also plans to rehabilitate the prison facilities and begin vocational training classes.

On a tour of construction at the prison in February, Lt. Col. John Voorhees, the battalion commander, said, “We’re trying to make the government the best alternative, in the right way.”

“This is the future,” he said.  

Under Mayar, the prison director, authorities have sought to find contraband such as cellphones that insurgents have used to plan attacks in the past. Afghan officials said they did not know whether the prisoners had been able to coordinate the escape with those outside or whether any prison guards were complicit.

Hamdard is a special correspondent. Staff writer Rajiv Chandrasekaran contributed to this report from Washington.