Tribal elders said Monday’s raid in the Bajur district near the Afghan border set back peace efforts in Pakistan’s northwestern tribal region, and a prominent human rights group demanded an independent inquiry.

Abdul Aziz Khan, head of Bajur’s council of tribal chiefs, on Wednesday demanded a guarantee there would be no further attacks, saying, "without it we will not begin talks with the government." At stake is a deal to stamp out militancy like that reached in September with tribal chiefs in North Waziristan.

Protests erupted for a third day in Bajur on Wednesday, with 10,000 tribesmen - including masked militants linked to al-Qaida - demanding the deaths of Pakistani President Gen. Pervez Musharraf and President Bush.

Musharraf’s government has been roundly condemned in Pakistan for the attack on the school in the village of Chingai, three kilometers (two miles) from the poorly demarcated border separating Pakistan from Afghanistan’s Kunar province, where U.S. troops have repeatedly battled al-Qaida militants.

Tribespeople and Islamic leaders denounced the raid as an illegitimate attack on innocent students and teachers and threatened retaliation.

Many people blamed the U.S. military for carrying out or providing intelligence for the attack. Residents reported seeing unmanned drone surveillance aircraft flying over the town. Pakistani officials denied U.S. involvement and said they had aircraft - provided by the Americans - capable of carrying out surveillance.

Pakistan’s chief army spokesman, Maj. Gen. Shaukat Sultan, said the military had no option but to use helicopter gunships against the school, which he said was a front for a militant training camp, because attempts to arrest suspected trainee terrorists could have led to their escape.

"The biggest factor that contributes to success is surprise," Sultan told The Associated Press. "If we lost the surprise by 10 minutes, the operation (was) likely to fail."

Sultan said evidence included students in their 20s seen conducting exercises outside the school, school leaders who told rallies they were preparing suicide bombers and other intelligence he declined to specify.

Pakistani troops have been preventing journalists, human rights monitors and political leaders from traveling to the site.

New York-based Human Rights Watch urged the government to let independent investigators visit the area to determine who carried out the attack, how it was planned and executed, and who was killed.

The group’s South Asia researcher Ali Dayan Hasan said the high number of dead pointed to use of excessive force.

Samina Ahmed, the South Asia project director for the International Crisis Group, said the military should have detained those inside the building, not killed them.

"There was not a fight going on at the time, it wasn’t in the heat of the battle," Ahmed said. "A more effective tactic would have been law enforcement, do a cordon-and-search, arrest people and try them."

Sultan, the army spokesman, declined to say if those in the school were armed, but said their training made them dangerous.

"We think the response was justified," he said.

Among those killed was Liaquat Hussain, a fugitive cleric who ran the school. The attack was launched after Hussain, an associate of al-Qaida No. 2 Ayman al-Zawahri, rejected government warnings to stop using the school as a terrorist training camp, Sultan said.

Another al-Zawahri lieutenant, Faqir Mohammed, left the school 30 minutes before the missile strike, according to an intelligence official.

A Pakistani official also claimed that al-Zawahri and al-Qaida’s operational commander in Kunar province, London terror plot mastermind Abu Ubaida, had visited the school, but were not there during the attack.

Musharraf’s government has been under U.S. and Afghan pressure to crack down on militants operating along the Pakistan-Afghan frontier. Russian foreign minister criticizes European draft resolution on sanctions against Iran