Thousands of Islamic hard-liners, angered by an airstrike on a religious school that killed 80 people, held rallies across Pakistan on Friday, denouncing President Gen. Pervez Musharraf and demanding government compensation for the families of the dead.

An opposition coalition, Mutahida Majlis-e-Amal, also called a strike that shutdown shops and public transport in Khar, near where Pakistan's army says its helicopters on Monday destroyed an Al Qaeda-linked school used to train militants fighting across the border in Afghanistan.

The school in the Bajur tribal region was run by Liaquat Hussain, a fugitive cleric who died in the airstrike and was a purported associate of Al Qaeda's No. 2 leader Ayman al-Zawahiri.

Residents and hard-line religious parties claim the attack was launched by U.S. drones and that the victims were either Islamic students or teachers. Pakistan and the U.S. military have denied American involvement.

In Bajur, some 3,000 tribesmen marched Friday along a road about two miles from the scene of the attack on Chingai village, not far from Khar. Another 2,000 people rallied in the town of Inayat Qala.

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"We reject the government claim that America is not behind this attack," tribal leader Akhwanzada Chitan said at the Khar rally, urging the government to apologize for killing "innocent people" and to pay compensation to their families.

"We will continue our protest until the acceptance of this demand," he said.

Thousands protested in Karachi, the southern border town of Chaman and the northwestern city of Peshawar. Hundreds more rallied in the cities of Lahore, Multan, Quetta and Islamabad. There were no reports of violence.

In a speech to about 3,500 Islamists in Peshawar, Maulana Fazalur Rahman, a senior MMA leader, condemned Washington and Musharraf for allegedly killing "innocent students and teachers" in Bajur.

Rahman said the signing of a peace accord between the government and tribal leaders in Bajur had been hours away until it was "sabotaged" by the airstrike. He added that "tribesmen know how to defend themselves, and I tell you that they will do it."

Angry tribesmen have already threatened a wave of suicide attacks on Pakistani forces in retaliation for the attack.

In response to criticism that the airstrike was unjustified and used disproportionate force, state-run Pakistan Television on Thursday broadcast an aerial surveillance video shot with an infrared camera that the government said showed men receiving militant training before the attack. The poor-quality video showed people doing simple physical exercises, such as leg stretches, and running in a circle. No weapons were visible.

In January, a U.S. missile attack hit a border village in Bajur where officials say al-Zawahiri had been due to attend a dinner. Thirteen civilians were killed, but reports that some Al Qaeda operatives also died were never confirmed. Al-Zawahiri was not hurt.

Meanwhile, pro-Taliban militants beheaded a Muslim teacher in the North Waziristan tribal region after kidnapping him over suspicion that he was spying for the U.S. forces in Afghanistan.

Villagers found the headless body of Maulvi Silahuddin, a madrassa teacher, early Friday. A letter found nearby read: "Anyone spying for America will face the same fate," a local security official said on condition of anonymity because he was unauthorized to speak to the media.

Pakistan is a key ally of the United States in its war on terror, and it has deployed about 80,000 troops in its semiautonomous tribal regions, from where Islamic militants are believed to cross over to Afghanistan to target Western forces.