The attack occurred in the eastern city of Lahore, far from the conflict-ridden northwest and on a block that bristles with security. It came as Pakistan's army appears to be gaining ground in its battle with Taliban insurgents in the northwest's Swat Valley, and Interior Minister Rehman Malik said it was probably carried out by the Taliban or its Islamist allies in retaliation for the military offensive, which began this month.  The blast was the third major terrorist attack in Lahore in as many months, and analysts said the choice of the location may indicate a desire by insurgents to strike back at the government on its turf. Lahore is the capital of Punjab, the nation's most populous province and the one that most top military commanders call home.  "This was an attempt to deter Pakistani authorities from taking action," said Hasan-Askari Rizvi, a Lahore-based analyst. "They thought that if they could demoralize the people here, that would have a lot of impact and be a restraining influence on the military."  Malik insisted that such a strategy would not succeed, telling reporters that insurgents had declared war on the state and that the government was determined to fight back.  "I believe that anti-Pakistan elements, who want to destabilize our country and see defeat in Swat, have now turned to our cities," he said.  Public opinion in the country has shifted over the past month toward greater support for the battle against the Taliban. It was unclear whether Wednesday's attack, which injured about 250 people, will increase that support or put pressure on the military to curtail its campaign.  The United States has leaned heavily on Pakistan to intensify its efforts against militancy, and Gen. David H. Petraeus, leader of U.S. Central Command, was in the capital, Islamabad, this week to meet with Pakistani officials. He told Radio Free Europe/Radio Liberty on Tuesday that he was encouraged by Pakistan's renewed efforts in Swat.  On Wednesday, the army reported progress in regaining control of the valley, predicting that Mingora, Swat's main city, would be back in government hands within three days. The Taliban has controlled Swat off and on since late 2007. The army's offensive there has left more than 1,100 insurgents and about 100 police officers and soldiers dead, according to the military. The battle has also caused more than 2 million civilians to flee.  Although the Taliban insurgency is rooted in northwestern Pakistan, along the border with Afghanistan, Islamist extremism is not confined to that area, and security remains a major problem across the country.  Wednesday's attack, one of the deadliest in Pakistan this year, occurred in front of two police buildings and an office of Pakistan's Inter-Services Intelligence agency, or ISI. The buildings are located on Mall Road, the busiest thoroughfare in a city known as a vibrant cultural hub. It was not clear which building was the intended target. The ISI has had a complicated relationship with militant groups in Pakistan; it once armed and nurtured them, but in recent years it has officially turned against them.  The attack began when gunmen crashed a car through a security barrier. Some got out and started firing at the ISI office, officials said. Security forces returned fire, and after a brief gun battle, the explosives-packed car blew up. The assailants continued to fire and hurled grenades for 10 to 15 minutes after the blast.  The blast collapsed one of the police buildings, an emergency response center known as Rescue 15, trapping people in the debris. It also sheared walls off the ISI office and brought down the ceilings of operating rooms in a nearby hospital, injuring 20 people. Officials estimated the size of the bomb at more than 200 pounds.  The explosion left an eight-foot-deep crater, with rubble spread across an area the size of a city block. Nine of the dead were police officers, and several intelligence officers were killed, officials said. Most of the injured were civilians who had been making their way through morning traffic. At least two suspects were arrested.  Lahore, once considered removed from the insurgents' violence elsewhere in the country, has become a target this spring. In March, four gunmen hurled grenades and opened fire on officers at a police training center on the city's outskirts, killing eight people and themselves. Only days before, assailants had attacked a bus carrying the visiting Sri Lankan cricket team, killing six police officers escorting the bus and a driver.  There was no immediate assertion of responsibility for the latest strike. But the army released Wednesday what it said was the transcript of an intercepted telephone conversation between Muslim Khan, a spokesman for Taliban fighters in Swat, and two other insurgents, apparently in the tribal area of Waziristan.  In it, Khan asks the others to attack "generals or colonels from Punjab so that they know the pain, or at the houses of army people so that their children also get killed."  "Yes, you are right," one of the others replies. "I will convey your message."
ISLAMABAD, Pakistan, May 27 -- The powerful car bomb that tore the walls off an office of Pakistan's elite intelligence service, ravaged a police facility and killed as many as 30 people Wednesday morning is the latest reminder that insurgents are able to strike almost anywhere in this country as...