ISLAMABAD, Pakistan — Suspected Islamic terrorists killed about 30 people and injured more than 250 Wednesday in a gun and vehicle-bomb attack in the eastern city of Lahore that may be the first major reprisal for Pakistan's military offensive against extremists, analysts and officials said.
The bomb contained as much as 220 pounds of explosives and reduced several buildings to rubble, among them a police station, an emergency services call center and offices of the Inter-Services Intelligence spy agency, along with a 200-yard stretch of the street.
The attack began when several assailants jumped from the vehicle, described by some witnesses as a van, and opened fire on the buildings with automatic weapons.
A senior Pakistani official said the ISI compound appeared to be the primary target of the attack, and it showed that the spy agency is now at war with Islamic extremist groups that it previously trained and armed to fight in India's disputed Kashmir region and in Afghanistan.
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"As far as the Taliban and al Qaida are concerned, they now consider the ISI as an enemy," said the official, who requested anonymity because he wasn't authorized to speak publicly.
However, the official suggested that terrorists who carried out the attack had learned the location and layout of the ISI compound because they'd been to meetings there.
"How did they (the attackers) know where the (ISI) headquarters are and where the vulnerable points were?" he asked.
Pakistani troops Wednesday continued to press their month-old offensive to reclaim the Swat Valley, about 100 miles from Islamabad, from al Qaida-allied Taliban insurgents, and the army said its forces would recapture Mingora, the main city, in a few days.
"I believe that anti-Pakistan elements, who want to destabilize our country and see defeat in Swat, have now turned to our cities," Interior Minister Rehman Malik said.
"This (attack in Lahore) is undoubtedly linked to Swat or the tribal area. It's linked to the insurgency," said Talat Masood, a retired army general.
There's been speculation, boosted by recent comments by President Asif Ali Zardari, that the army will extend the operation to the Waziristan region in the tribal area along the border with Afghanistan, the epicenter of Pakistan's Islamic insurgency and Osama bin Laden's suspected hideout.
"Pakistan will have to adjust, take a lot of preventative measures," Masood said. "They're hitting the security apparatus, the same pattern we've seen before."
Lahore, Pakistan's cultural center and the capital of the country's most populous province, Punjab, was the target of two major terrorist strikes in March.
In the first attack, gunmen opened fire on a visiting Sri Lankan cricket team and its police escort. Days later, a commando-style squad stormed a police academy in an operation claimed by Baitullah Mehsud, the Waziristan-based leader of Pakistan's main Taliban alliance.
The use of firearms in the latest assault could link it to the same or similar groups behind the March attacks.
There were several terrorist strikes last year in Lahore, including a massive vehicle bomb at the local headquarters of the Federal Intelligence Agency, a civilian intelligence agency.
Police think that the Taliban are working with militant groups in Punjab. In particular, police point to the feared Lashkar-e-Jhangvi, a Sunni Muslim organization that began with attacks on minority Shiites but has fallen under al Qaida's influence.
"Our intelligence-gathering systems have to deliver better," said Rustam Shah, an analyst who formerly was Pakistan's ambassador to Afghanistan. "We just go from one incident to another. The real culprits are not nabbed and their sponsors are never identified. Pakistan's administrative weakness allows these attacks."
U.S. Ambassador to Pakistan Anne W. Patterson said in a statement that the terrorist strikes "serve only to highlight the vicious and inhuman nature of this enemy whose true target is the democratically elected government of Pakistan and the security of all Pakistanis as well as the global community."
(Shah is a McClatchy special correspondent. Jonathan S. Landay contributed to this article.)
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