KABUL (Reuters) - Hundreds of prisoners escaped from a jail in Afghanistan's south on Monday through a tunnel dug by Taliban insurgents, a major setback for Afghan and foreign forces just before the start of the traditional summer fighting season.
Tooryalai Wesa, governor of volatile Kandahar province, said 488 prisoners escaped from the province's main Sarposa jail. The Taliban said 541 prisoners crawled their way to freedom.
Here are some facts about the tunnel and how the Taliban's great escape was carried out.
With time and patience, and most likely inside help. The 320-metre long tunnel was started in a house within sight of the prison and the Taliban, who often make exaggerated claims, say it took five months to build. That means digging began early in the winter, probably around November or earlier. The house had been rented for eight months and the tunnelling likely began soon after the house was secured.
Images released so far show a hole about one metre wide, descending into compacted dirt with footholes in the tunnel sides. A fan beside the entrance may have been used to direct fresh air inside the shaft. Two steel poles with flat discs at each end were used to place car jacks under the concrete cell floor, which was several inches thick, cracking it open.
It is still unclear if the tunnel was reinforced to ensure it did not collapse during winter rains. Afghan authorities say the shaft was later mined with explosives, making full inspection impossible until it was cleared.
Also unknown is how the Taliban builders judged its length so accurately, bringing the tunnel up into a cell used for insurgents, and how the prisoners then managed to escape at a rate of more than 100 an hour through such a narrow hole.
The Sarposa prison governor said the cell block was more like a secured compound, with prisoners free to move between rooms and no lock on individual doors. Entrance to the compound was via a single high-security gate.
The escapees included Pakistani insurgent fighters, Afghan Taliban and broader political prisoners. The Taliban say more than 100 were senior commanders but that is unlikely because most of the top Taliban leaders are believed to be in Pakistan. The "leaders" were more likely mid-level field organisers.
Many have probably fled to Pakistan, General Ghulam Dastgir, the governor in charge of the jail, said. Security has been tightened along the often-porous 2,400 km (1,490 miles) border. Around 26 have already been recaptured and Dastgir said biometric data held on all prisoners would help snare others.
Still, many of the prisoners are experienced fighters and their escape is a blow coming so close to the start of the fighting months, and after a concerted NATO and Afghan campaign to capture militants over the past year.
If some stay in Afghanistan and are not recaptured, the spectacular breakout could provide reinforcements for the Taliban at a time when foreign troops in the country are looking to start winding down their combat involvement, ending it altogether by the end of 2014.
The government and President Hamid Karzai's spokesman have promised a full investigation before taking action. But it would seem likely that security procedures at the jail will be tightened in the short term after the second mass breakout in only three years. Dastgir's job would also seem precarious.
In 2008, around 1,000 prisoners including Taliban fighters escaped after a truck bomb blew open the jail gates. That mass escape quickly led to a surge in fighting.
After the 2008 breakout, Canada's government spent millions of dollars upgrading the gates and guard towers at the prison, as well as training its staff, including increased pay to counter the lure of Taliban bribes.
Another upgrade and round of training could be possible, including regular night patrols inside the room compounds holding insurgents, rather than prison staff just standing guard at the entrance gate.
But the breakout could also lead worried U.S. officials to delay plans for a transition to Afghan control at the American-run prison at Bagram air base, north of Kabul, agreed last year.
The Bagram jail houses many of the most dangerous insurgents, but has been heavily criticised by human rights groups who have compared it to the U.S. detention centre in Guantanamo Bay, Cuba.
Reporting by Rob Taylor; Editing by Paul Tait and Alex Richardson