The attack broke what had been a relative lull in violence in Pakistan, where militant groups revile the government for its alliance with the US It also showed that insurgents retain the ability to strike the country's heartland, far from the Afghan border regions where Al-Qaeda and the Taleban have long thrived, despite army offensives aimed at wiping them out.
Pakistanis living near the building had filed complaints urging authorities to move the unmarked interrogation facility out of the residential area so the street wouldn't become a target for an attack, said Mohammad Musharraf, a neighborhood resident.
The Pakistani Taleban claimed responsibility in a telephone call to an Associated Press reporter. It and allied groups are believed responsible for a wave of attacks that killed more than 600 people starting in October, including several in major Pakistani cities. More recent attacks have been smaller and confined to remote northwest regions near Afghanistan.
The bomb blast Monday comes amid reports of a Pakistani crackdown on Afghan Taleban and Al-Qaeda operatives using its soil. Among the militants said to have been arrested is the Afghan Taleban's No. 2 commander, Mullah Abdul Ghani Baradar. In recent days, Pakistani officials say an American member of Al-Qaeda has been captured in the southern city of Karachi.
The explosion went off outside a Punjab province police building, police official Zulfikar Hameed said. TV footage showed a huge crater in the ground where the blast originated. It appeared the suicide bomber rammed a car packed with as much as 1,300 pounds (600 kilograms) of explosives into the building's perimeter wall, officials said.
“This place was used to interrogate important suspects, but presently there was no such suspect, but more than 40 staff were manning the place,” Lahore police chief Pervez Rathore said.
Noorul Huda, a student at a nearby religious school, was in his first class when the blast shook the area, he told TV reporters.
“With the huge bang, blocks and pieces of the roof fell upon us and six of us were wounded,” said the young man, who suffered a head injury that was covered by a bloodstained cloth. “It was total chaos outside and people were running and crying for help.” Musharraf, who lives near the building, said his son was injured.
“My whole house was shaken and I thought it was an earthquake,” he said. “A window dislodged and fell on my son, fracturing his arm.” Police official Chaudhry Shafiq said 13 people had died.
Of the 61 people wounded, several were in critical condition. Major Mushtaq, who heads the interrogation facility, said the dead included nine officials from police and the investigation agency and four civilians, including two women.
Hospital official Jawed Akram said the dead included at least one woman and a young girl, apparently part of a group heading to a school. Several women were among the wounded.
“People are coming with multiple wounds, many with head injuries and broken limbs,” Akram said.
Interior Minister Rehman Malik painted the attack as sign of desperation from militants whose “backs have been broken” by the army.
“They are taking guerrilla actions but gradually it is decreasing and they are being arrested and in the coming days they will have no chance,” Malik said.
Much of the police building collapsed, leaving piles of bricks and metal, TV footage showed. Other nearby homes and other buildings, including a mosque, also were damaged.
Militant attacks in Pakistan frequently target security forces, though civilian targets have not escaped.
During the bloody wave of attacks that began in October - coinciding with a major army ground offensive against the Pakistani Taleban in South Waziristan tribal area - Lahore was hit several times.
In mid-October, three groups of gunmen attacked three separate security facilities in the eastern city, a rampage that left 28 dead. Twin suicide bombings at a market in Lahore in December killed nearly 50 people.
The US has applauded Pakistan for its military operations and is also suspected of pummeling militants in the tribal areas with dozens of drone missile strikes, including one Monday that killed three people, said Pakistani intelligence officials.
The attack, carried out by a drone that fired at least two missiles at a house in North Waziristan, also wounded one man, said the officials, speaking on condition of anonymity because they were not authorized to talk to the media.
The three dead were foreigners, but their nationalities were not known, said the officials.
Washington refuses to discuss publicly the covert drone program in Pakistan, but officials say privately it has killed several senior Al-Qaeda and Taleban commanders.
