PESHAWAR, Pakistan – Pakistan’s army destroyed a major al-Qaida hide-out and arrested 21 suspected militants, including foreigners, and a government official accused of helping them in a remote northwestern tribal region near Afghanistan, a military commander said Tuesday.

During the four-day operation, thousands of troops seized a cache of weapons, including bombs, detonators and rockets; communications equipment used to exchange messages with militants in Afghanistan; and propaganda CDs and literature. The operation coincided with a visit by President Gen. Pervez Musharraf to the U.N. summit in New York.

“It is the biggest-ever operation, which is still going on in North Waziristan,” Lt. Gen. Safdar Hussain, the top army commander responsible for anti-terrorism operations in northwestern Pakistan, told a news conference.

“As a result of this operation, a center of al-Qaida and terrorists has been destroyed and the back of al-Qaida and terrorists has been broken in the tribal areas because terrorist activities were carried out from here.”

Hussain said foreigners and “some important men are included among the captured people,” although he would not elaborate.

Although Musharraf is an ally of Washington, his government has been criticized by American, Afghan and U.N. officials over cross-border militant attacks at targets inside neighboring Afghanistan. Violence has escalated there ahead of key parliamentary elections set for Sept. 18.

Musharraf says he has offered to build a security fence at the border to deter incursions by militants and drug traffickers from Afghanistan.

The latest operation came in the same area where suspected militants slit the throats of three people Monday and threw their bodies in a drain in a village east of Miran Shah on suspicion they were spies.

According to residents and officials, a note pinned on one victim said, “Anybody who works as a spy for America will have to face the same fate.”

Militants in the past three years are believed to have killed about 70 tribal elders and their associates for helping the Pakistan army’s counterterrorism operations.

Hussain said more than 3,500 troops backed by helicopter gunships were dispatched Tuesday to three areas of North Waziristan after confirmation of reports that al-Qaida militants were hiding there.

Some of those arrested were from at a compound near a religious school set up by senior Taliban commander Jalaluddin Haqqani, he said.

Hussain said Haqqani’s driver — caught this week in Miran Shah, the main town in North Waziristan — led the military to the compound, which was being used to send messages inside Afghanistan in Arabic and Pashtu, the language spoken by most Taliban.

“We dismantled this communication center and seized a large number of CDs and communication equipment,” Hussain said.

Troops also arrested a junior government official from North Waziristan and a close relative of Maulana Nek Zaman, a lawmaker from a religious party, on suspicion of helping terrorists, he said.

Pakistan has deployed about 80,000 troops in its tribal regions to stop remnants of al-Qaida and Taliban from sneaking into Pakistan or going back to Afghanistan, where U.S.-led coalition forces and Afghan government targets are often attacked.