ISLAMABAD, Pakistan - A prominent Pakistani cleric who had publicly condemned the Taliban and its suicide-bombing attacks was killed yesterday by a teenage suicide bomber who detonated explosives inside his office at an Islamic seminary in the eastern city of Lahore.

Sarfraz Naeemi, a renowned religious scholar, had spoken openly of his support for the ongoing government military offensive to root out Taliban militants from the Swat Valley and surrounding regions. His death sparked immediate protests on the streets of Lahore by followers angry at the Islamic militant group and at the lack of security provided by police to Naeemi and his seminary.

The bombing, which also killed at least three other people, was one of two devastating attacks yesterday in Pakistan, where a wave of retaliatory strikes continued in the wake of the government's bid to crush the Taliban.

In the city of Nowshera, 60 miles west of Islamabad, the Pakistani capital, a suicide bomber drove an explosives-laden truck into a mosque at a military installation, killing at least six people and wounding at least 90.

The Pakistani Taliban claimed responsibility for both attacks.

Experts have said the Taliban's strategy is to cause enough mayhem to erode public support for the six-weeks-long offensive. The military has methodically cleared the Taliban out of much of the Swat Valley and the nearby regions of Buner and Lower Dir, and has begun to direct its forces toward pockets of militants in the Bannu region just outside the semiautonomous tribal areas of Waziristan, where pockets of Taliban and al-Qaeda extremists have been entrenched.

But as the Pakistani government has made substantial gains, it has struggled to cope with the outbreak of increasingly sophisticated, almost daily suicide revenge attacks.

Attacks on police and intelligence agency buildings in Lahore on May 27 and on an upscale hotel in the city of Peshawar on Tuesday were well-planned commando-style operations in which the killers breached heavily fortified entrances by firing at guards before driving vehicles inside the complexes and detonating their explosives.

At Jamia Naeemia seminary where Naeemi was killed yesterday, students complained that security had not been increased despite death threats received by the cleric. Naeemi had outspokenly denounced the Taliban and, on June 2, led hundreds of followers through the streets of Lahore in a rally in support of the military operation in the Swat Valley.

"We want to tell the people who killed him that Sarfraz's death does not mean that his mission has been stopped," Naeemi's brother, Tajwar, said yesterday. "We will continue his mission."

Witnesses said the bomber was a teenage boy who entered Naeemi's office after Friday prayers.

"Thirty seconds later, there was a big blast," said one of Naeemi's students, who asked not to be named. The explosion injured six people. Naeemi was rushed to the hospital but died en route.

Afterward, angry students took to the streets, shouting, "Down with the Taliban!" and burning tires. Naeemi's son, Waqar, pleaded with protesters to exercise restraint, telling them that revenge would contradict his teachings.

"His death is a very significant event," said Khalid Zaheer, a Pakistani professor and religious scholar. "He was one of the most prominent scholars who stood up clearly against suicide bombings and against the Taliban. His argument was simple: Religion does not stand for violence. You can't take the life of any individual or your own life. And you can't wage jihad against your own state."