Top government ministers from 21 Pacific Rim nations (search) convened high-level talks on free trade and global security Wednesday as police battled university students protesting the summit and a weekend visit by President Bush (search).

Several hundred demonstrators who tried to gather in downtown Santiago were confronted by riot police, who doused them with tear gas from fast-moving jeeps and knocked them to the ground with blasts from water cannons mounted on trucks.

There were no immediate report of injuries and the protest occurred miles away from the suburban Santiago venue for the annual Asia-Pacific Economic Cooperation (search) forum. But official media reported that 120 protesters were taken away in buses. Among those detained and later released was Rodrigo Soto, who heads Amnesty International's Chile office.

Protesters voiced a range of causes, including opposition to the U.S.-led war in Iraq and concern that unfettered capitalism widens the gap between rich and poor.

After being repulsed, the crowd of mostly university students fled but managed to regroup, shutting down traffic and yelling, "Get out of here, Bush," and "We don't want to be an American colony."

Secretary of State Colin Powell arrived in Santiago late Wednesday night to meet with APEC ministers. Bush is to meet with other APEC leaders, including Chinese President Hu Jintao and Japanese Prime Minister Junichiro Koizumi, at the summit this weekend after the ministers conclude their discussions.

It was the second straight day of protests and more are expected this week, including a government-authorized march on Friday through the streets of Santiago. Protesters vehemently oppose the U.S.-led war in Iraq and globalization, which they characterize as uncontrolled capitalism that widens the gap between rich and poor.

APEC foreign ministers and trade ministers met on issues ranging from fighting terrorism and corruption to a proposal to create a free trade area that would link the Americas to Asia. National leaders will gather Saturday and Sunday.

Bush is expected to bring up North Korea during the summit, urging other leaders involved in multinational talks to persuade the reclusive nation to abandon its nuclear ambitions.

Bush administration officials also are expected to press China to change its currency practices. For more than a year, the Bush administration has been pressuring China to stop linking its currency at a fixed rate to the U.S. dollar, which American manufacturers contend has resulted in the Chinese currency being undervalued by as much as 40 percent. That gives Chinese products a competitive advantage against U.S. goods.

The ministers' agenda included discussion of a recent proposal by APEC Business Advisory Council, the group's business lobby, to consider creating a Free Trade Area of the Asia-Pacific that would stretch from China to California and from Australia to Chile's southern tip.

Hernan Somerville, a Chilean who heads the advisory council, said such a zone "could bring significant economic benefit to the region as a whole" by slashing tariffs and opening markets.

The group asked APEC leaders to establish a task force to study the issue, but a trade zone spanning the Pacific Ocean would take years to create.

Experts say any free trade zone will not be taken seriously until the APEC nations decide on a framework for actual negotiations. Huang Chih-peng, a top Taiwanese trade official, said ministers are sure to discuss the idea but said it's unclear what the world leaders will decide.

APEC, which represents the United States, Canada, Japan, Russia, China and most southeastern Asian economies, accounts for more than half of the world's trade.

A trade deal among APEC nations would form a bloc dwarfing the European Union and the proposed Free Trade Area of the Americas now under negotiation for a land area spanning from Alaska to Argentina.

APEC has been working for years on a plan to reduce tariffs among developed countries in the group by 2010 and among developing member nations by 2020. Critics say member economies have made little progress toward these goals.