By LARRY ROHTER
 
SANTIAGO, Chile, Nov. 19 - Using tear gas and water cannons, riot police officers dispersed hundreds of rock-throwing protesters on Friday after thousands of people had gathered peacefully to demonstrate against the presence of President Bush at a weekend summit meeting here.

Mr. Bush, in his first trip abroad since his re-election, is one of 21 world leaders scheduled to attend the annual Asia-Pacific Economic Cooperation conference, being held here for the first time. The group, known as APEC, aims to encourage economic growth and trade among member nations, who account for more than half of the world's economy. The Chilean government has trumpeted the decision to hold the meeting here as an indication that this country of 15 million has achieved elite status.

Protest organizers said 30,000 people took part in the late morning march, which followed a convoluted route through downtown streets, far from the actual site of the conference in a remote convention center surrounded by a mountain range. The police refused to offer an estimate, and local radio stations put the number of marchers at about 15,000.

The protesters, a combination of graying veterans of the Allende era, mixed with younger environmental advocates, Indian groups, punks, goths and anarchists, said APEC fostered economic inequality, and they criticized Mr. Bush for the war in Iraq. They carried placards and banners portraying Mr. Bush as a vampire, carrion-eating vulture, demon and ghost, as well as Cuban flags and a large Iraqi flag with the exhortation, "Hang on, Falluja!"

"We want Bush to know that he is not welcome here," said Mónica Cerón, a college student who was wearing a "Bush Stinks" T-shirt and a red headband that with the words "Down with Bush" and a hammer and sickle. "Our government may want to do business with him, but the Chilean people oppose his genocidal war on Iraq and his designs on Latin America."

Citing the same international accords that made possible the detention of Gen. Augusto Pinochet in Britain in 1998, opposition groups here even filed a complaint to have Mr. Bush held as a war criminal. A judge dismissed the complaint early this month, however, arguing lack of jurisdiction.

A few older demonstrators also complained of American support for the military coup that overthrew Allende on Sept. 11, 1973. Secretary of State Colin L. Powell offered an indirect apology for that policy last year, saying it was "not a part of American history we are proud of." But marchers like 58-year-old Tomás Soto described the episode as "an example of the kind of state terrorism that the United States always claims to be against."

Friday's march, organized by the Chilean Social Forum and nearly 100 other groups opposed to corporate-led globalization, was the only legal means of mass protest the government was willing to authorize during the conference. But some other left-wing and anarchist groups have defied that ban and led smaller street protests of their own all week, resulting in rock-throwing confrontations with the police and several hundred arrests.

Security precautions have been extraordinary by Chilean standards, with an estimated 4,000 police officers in the streets or around leading hotels, helicopters in the air, streets blocked off and armored cars in reserve. The government declared a holiday here in the capital on Friday to encourage people to stay off the streets, but that only seemed to encourage university students to join the protests.

In a flier distributed to schools and government offices, the national police warned that "Chile may be at the end of the world, but for international terrorism, nothing is far enough away." The text made little distinction between antiglobalization and terrorist groups and urged citizens to report any "suspicious attitudes" or "the places of anti-APEC meetings" to authorities.

Sara Larraín, one of the organizers of the protest, called the police flier "an effort to intimidate and spread fear."

"We're not bomb throwers," she said. "We want to confront APEC, but only in the realm of ideas and paradigms.