ISLAMABAD, Pakistan - Thousands of antigovernment protesters demanded yesterday that Pakistan shut the route along which supplies are ferried to U.S. and NATO forces in Afghanistan, adding to the growing pressure on Islamabad's beleaguered leadership.

The demonstration by more than 10,000 people in the city of Peshawar also focused on a recent series of U.S. missile strikes against suspected al-Qaeda and Taliban targets in Pakistan's lawless tribal areas along the Afghan border and on Pakistani military offensives against Islamic insurgents in the area.

Leaders of the demonstration drew links between the missile attacks and the supply line, saying the equipment was being used for attacks on Pakistani soil and vowing to shut down the convoys.

"We will no longer let arms and ammunition pass through . . . and reach the hands of American and NATO forces in Afghanistan," Sirajul Haq, provincial head of the hardline Islamist party Jamaat-e-Islami, told the crowd. "They are using the same against our innocent brothers, sisters and children."

The supply line - along which gear passes from the Pakistani port city of Karachi and through the Khyber Pass - has increasingly come under assault, leading U.S. and NATO forces to scout possible alternative routes.

Hundreds of vehicles, including Humvees allocated for the Afghan army, have been torched in recent weeks in arson attacks on terminals, leaving several security guards dead. The convoys also are targets in Afghanistan, despite armed escorts.

But Pentagon spokesman Bryan Whitman said yesterday that convoys continue to flow along the route at the rate of about 150 trucks a day and said the attacks "have not affected our ability to operate at this point" in Afghanistan.

"It continues to be a viable supply route. That said, we are looking at ways not only to improve the security along that route but other alternatives to it," he said.

Yesterday's rally appeared to be the largest against Western use of the route since Pakistan's civilian government took office in March and one of the largest antigovernment protests so far. Banner-toting demonstrators chanted "Down with America" and "Jihad is the only solution of America" as they marched.