Islamabad, Pakistan ? The Pakistani government intensified a dangerous hunt Thursday for 40 suspected al-Qaida men near the Afghan border, sending 100 more infantrymen to scour a mountainous border region inhabited by fiercely independent, armed tribesmen who often have al-Qaida sympathies.

The troops, backed by helicopters and armored vehicles, joined more than 500 other soldiers who have been in the area since Wednesday, when the suspected al-Qaida fighters opened fire on Pakistani soldiers, killing ten, including a captain and a major. More soldiers were wounded.

An army officer in the North West Frontier Province, who spoke on condition of anonymity, said soldiers were carrying out ID checks of those leaving or entering the area.

He said troops also destroyed a house where the fighters had hidden as a warning to those locals who support al-Qaida and Afghanistan’s ousted Taliban regime.

Pakistan military spokesman Gen. Rashid Quereshi said soldiers had arrested “some al-Qaida men” since Wednesday morning, but he refused to elaborate. It was not clear if those arrested were linked to Wednesday’s attack.

The fight broke out before dawn when soldiers approached a suspected al-Qaida hideout near the town of Wana, about 300 kilometers (190 miles) west of Islamabad, in South Waziristan, a mountainous area on the Afghan border dominated by tribal elders, largely outside the control of the Pakistani government.

More than 40 men attacked them with rocket-propelled grenades, assault rifles and hand grenades, the army said.

Officers said three al-Qaida fighters then engaged the army in a prolonged firefight while the others fled under cover of darkness. Two fighters were killed and one, a 15-year-old boy, was captured.

The fighters are believed to be Chechen members of al-Qaida who fled to Wana after the U.S. military’s Operation Anaconda in southeastern Afghanistan in March. The nationality of the captured teen-ager was not made public.

The Pakistani casualties were the first since President Gen. Pervez Musharraf, a key U.S. ally in the war on terror, deployed troops to the area, bordering the Afghan provinces of Paktia and Paktika, last year to intercept al-Qaida and Taliban members fleeing U.S. military attacks.

The United States put its forces in neighboring Afghanistan on alert to provide help if Pakistan requested it, but it had not, U.S. Gen. Richard Myers, chairman of the Joint Chiefs of Staff, said Wednesday.

“While U.S. forces were not involved in the fight, we appreciate the Pakistan army’s efforts to locate the al-Qaida,” Myers said.

In the tribal belt, Americans are often referred to as “the enemy” by even non-combatant local people and are clearly not welcome in the area.

“We will give full support to the Pakistan army in efforts to arrest al-Qaida men,” said Naseemulaah, a local tribal elder who uses only one name. “But no Americans should enter our area. We will not tolerate it.”

However, the fiercely proud tribesmen, many who possess assault rifles, grenade launchers and mortars, refuse to allow house-to-house searches even by Pakistani authorities, further impeding the hunt for al-Qaida members.

During recent weeks, local government buildings and Pakistani troops have come under sporadic rocket and machinegun fire from unknown attackers in the area.

U.S. officials estimate that up to 1,000 al-Qaida fighters still operate in small groups on both sides of the mountainous border.

In Pakistan’s biggest city, Karachi, police said Thursday they had arrested eight people, including three Palestinians and two Sudanese, as part of the investigation into deadly bombings at the U.S. Consulate and a hotel in southern Pakistan.

The detainees were the latest foreigners apprehended in connection with the attacks, which officials suspect were the work of Islamic militants possibly aided by al-Qaida.

The June 14 blast outside the consulate killed at least 12 Pakistanis and injured 50. In the May 8 suicide bombing outside the Sheraton Hotel, 11 French engineers and three other people died, including the bomber.

Pakistani police, with the help of the FBI, are investigating whether the attacks were linked, and if there is a connection to the kidnap-slaying of Wall Street Journal reporter Daniel Pearl and the March 17 grenade attack on a church which killed four people, including two Americans.