Islamabad, Pakistan ? Missiles fired by Pakistani helicopters destroyed a religious school on the Afghan border Monday that the military said was a front for an al-Qaida training camp, killing 80 people and prompting strong protests against the country’s president and the United States.

Islamic leaders and al-Qaida-linked militants called for nationwide demonstrations today to condemn what they claimed was an American assault on Pakistani soil. The army said those who died were militants, but furious villagers and religious leaders said the pre-dawn missile barrage killed innocent students and teachers at the school, known as a madrassa.

U.S. and Pakistani military officials denied American involvement and rejected claims that children and women died in the strike that flattened the building in the remote northwestern village of Chingai, two miles from the Afghan border.

President Gen. Pervez Musharraf has been under intense pressure, particularly from the United States and Afghanistan, to rein in militant groups, particularly along the porous Pakistan-Afghan frontier, where Osama bin Laden and his deputy Ayman al-Zawahri are believed to be hiding. The Pakistani leader, along with Afghan President Hamid Karzai, met with President Bush in Washington last month to address the issue.

Among those killed in Monday’s attack was Liaquat Hussain, a cleric who had sheltered militants in the past and was believed associated with al-Zawahri. The raid was launched after the madrassa’s leaders, headed by Hussain, rejected government warnings to stop using the school as a training camp for terrorists, said army spokesman Maj. Gen. Shaukat Sultan.

The raid threatens efforts by Musharraf to persuade deeply conservative tribespeople to back his government over pro-Taliban and al-Qaida fighters, who enjoy strong support in many semiautonomous regions in northern Pakistan. The planned signing of a peace deal between tribal leaders and the military was canceled Monday in response to the airstrike.

Protests were held from the northwestern city of Peshawar to the southern city of Karachi, the largest taking place in Chingai and the Bajur district’s main town of Khar, where 2,000 tribesmen and shopkeepers chanted “Death to Musharraf! Death to Bush!”

Amid fears of unrest, Britain’s Prince Charles, who arrived in Pakistan on Sunday for a five-day stay, canceled a visit planned for today to Peshawar.