Thousands of protesters rampaged through two cities Tuesday, storming into a diplomatic district and torching Western businesses and a provincial assembly in Pakistan's worst violence against the Prophet Muhammad drawings, officials said. At least two people were killed and 11 injured.

Security forces fired into the air as they struggled to contain the unrest in the eastern city of Lahore, where protesters burned down four buildings housing a hotel, two banks, a KFC restaurant and the office of a Norwegian cell phone company, Telenor.

U.S. and British embassy staffers were confined to their compounds until police dispersed the protesters, some of whom chanted, "Death to America!"

Witnesses said rioters also damaged more than 200 cars, dozens of shops and a large portrait of President Gen. Pervez Musharraf. Vandals broke the windows of a Holiday Inn, Pizza Hut and McDonald's.

Two movie theaters were torched, and clouds of tear gas and black smoke from burning vehicles drifted through streets in the city center.

A security guard shot and killed two protesters trying to force their way into a bank, Interior Minister Aftab Khan Sherpao said, adding that paramilitary forces were deployed to restore order.

Mohammed Tariq, a doctor at the state-run Mayo Hospital, said three people were being treated for serious bullet wounds, and eight more suffered injuries during clashes with police.

The protest was organized by a little-known religious group supported by local trade associations and one of the main Islamic schools in the city. Intelligence officials, however, suspected that members of outlawed Islamic radical groups may have incited the violence.

Raja Mohammed Basharat, law minister for Punjab province, of which Lahore is the capital, said the organizers promised Monday that the demonstration would be peaceful. No one has been arrested for the violence, but those responsible would be punished, he said.

The unrest began Tuesday in the nation's capital, Islamabad, about 180 miles northwest of Lahore, when between 1,000 and 1,500 people, mostly students, marched into a fenced-off diplomatic enclave through the main gate, as about a dozen police looked on.

The stick-wielding crowd charged about a half-mile down the road to the British High Commission, or embassy, where the students rallied briefly until police fired tear gas.

Outside the enclave, protesters smashed street lights and burned tires while chanting "Death to America!" and other slogans. Police rounded up about 50 protesters and put them in pickup trucks.

Another protest in Islamabad drew about 4,000 people. Separately, about 50 lawmakers from religious and moderate parties marched from Parliament to the diplomatic enclave, where they stood silently for five minutes before dispersing.

Hard-line cleric Hafiz Hussain Ahmad, senior leader of an opposition coalition of six religious parties, said, "We have come to the doors of the embassies to take our voice to the ambassadors. There is anger in the Islamic world. If they do not listen, their problems will increase."

People in this conservative Muslim nation have been enraged by the publications of the drawings, which first appeared in a Danish newspaper in September. Papers in other countries, mostly Europe but including some in the United States, reprinted them.

One of the caricatures depicts Muhammad wearing a turban shaped as a bomb with an ignited detonator string.

Islam widely holds that representations of Muhammad are banned for fear they could lead to idolatry.

There have been a series of mostly peaceful protests across Pakistan against the cartoons, and last week Parliament adopted resolutions condemning the drawing. Lawmakers also called for a nationwide strike on March 3.

But Aitzaz Ahsan, a lawmaker with the opposition Pakistan Peoples Party, said he will propose that the government call off the March 3 protest strike because of the prospect of further violence.

"It's really gotten out of hand," Ahsan said. "The violence is spiraling out of control."