By DAVID E. SANGER and LARRY ROHTER
 
SANTIAGO, Chile, Nov. 21 - President Bush's visit to Chile ended on a bizarre note here this evening when the Chilean government disinvited more than 200 guests to a dinner with the president rather than let the Secret Service screen them for weapons on their way into the presidential palace.

Mr. Bush and President Ricardo Lagos of Chile did not mention the dispute when they held a news conference at the palace this evening, with Mr. Lagos hailing the "modern and mature" relationship between Chile and the United States. "Most of the time we will be in agreement," he said. "Sometimes we won't."

On this trip, the disagreements were more visibly on display. On Saturday night, attending a dinner with leaders from the 21 countries that make up the Asia-Pacific Economic Cooperation summit that was meeting here, Mr. Bush had to wade into a group of security agents to pull his lead Secret Service agent out of a shoving match with the Chilean police. The tape showing the president assuring the Chileans that his agent could come with him played over and over on television screens in the region this weekend.

By Saturday night - though it had not been announced - Chile had already begun calling the guests to the dinner planned for Sunday at La Moneda, the presidential palace that was the site of the coup that overthrew Salvador Allende on Sept. 11, 1973. The dispute over the dinner on Sunday centered on the question of whether the Chilean guests would be required to go through metal detectors before dining with Mr. Bush, a standard practice for the Secret Service. The Chileans told Mr. Bush's delegation that the practice was humiliating. "Can you imagine someone like the Chief Justice of the Supreme Court having to submit to an inspection by gringo security agents in order to get into our own seat of government?" asked one of the disinvited Chileans, who spoke on condition that he not be identified. "That's an affront no Chilean was going to tolerate, and Lagos had no choice but to act the way he did."

In the United States, such screening has become such standard practice that when Mr. Bush attends an event at a stadium, tens of thousands of people are put through the airport-style magnetometers.

Not here. So instead of the gala, Mr. Lagos quickly downsized the event to a "working dinner" limited to a handful of senior staff members. Among White House aides and correspondents on the trip, no one could remember the last time a long-planned dinner had been scaled back so abruptly.

It clearly lessened the glow of a trip that Chilean officials had hoped would highlight their status as Washington's best friend and closest ally in South America, and as a partner in a recently ratified free trade agreement.

"Success of our free trade agreement is a model for other countries," said Mr. Bush, who came to office with an aggressive agenda for expanding trade with Latin America that had been largely derailed after the 2001 terror attacks.

"Exports have risen dramatically in both our countries, and both the Chilean people and the people of the United States have benefited,'' he said. "And through the establishment of free trade in the Americas, we are committed to a future in which every free nation in the hemisphere can share in the benefits of open markets and in the creation of new jobs."

Despite the economic closeness, Mr. Bush received what appeared to be a cool reception here. No crowds were on the streets to greet him as his motorcade sped through the city to the presidential palace late this afternoon, only small clutches of protesters.

A Chilean reporter reminded Mr. Bush at the news conference that Mr. Lagos had opposed the Iraq war, and he then asked the president, "Who was right and who was wrong?" Mr. Bush offered a defense of his action, but only after saying: "President Lagos didn't agree with my decision, and I respect that. He's still my friend."

Earlier, Mr. Bush met with President Vicente Fox of Mexico, the foreign leader with whom he was closest when he came to office. Relations grew far more distant after Sept. 11, when action was delayed on Mr. Bush's plans for loosening immigration rules.

Congress has balked at Mr. Bush's plan to change the law so that millions of illegal Mexican laborers could obtain temporary work visas in the United States but would not be able to use those visas as path to obtain citizenship. Mr. Fox is under pressure to persuade the president to expand the plan, and Mr. Bush said Sunday that he would use the political capital he gained in his re-election to get it passed.

"We'd much rather have security guards chasing down terrorists or drug runners or drug smugglers than people coming to work," he said. "And so, therefore, I think a guest worker program is important, and I look forward to working with Congress on it."

Mr. Bush said at the news conference that at the meeting of Pacific rim leaders he was asked a number of questions about the fall in the value of the dollar - a major issue for Asian and Latin American nations that are finding their products less competitive on the international market. He was also asked about America's soaring budget deficits - the kinds of questions his father used to receive in Japan in the late 1980's, before the deficits were turned to surpluses in the late 1990's.

"The best way to affect those who watch the dollar's value is to make a commitment to deal with our short-term and long-term deficits," Mr. Bush said.

The Asia-Pacific Economic Cooperation forum began in 1993 as a counterweight to the annual meeting that brings the American president together with old allies - Canada, Britain, France, Germany, Japan and Italy - and most recently with Russia.

After a dozen years, the meetings have allowed the American president to have at least one annual, face-to-face meeting with the leader of China - something that previously required endless, difficult negotiations over which leader would visit the other. (Mr. Bush and Hu Jintao, the Chinese president, agreed Saturday that each would visit the other next year.)

Perhaps more important, it brings together important regional heads of state who rarely have high-level interchanges with Washington, including the leaders of Vietnam and Indonesia. It is also a chance for small nations to showcase their progress - as Chile did this year, and Brunei did in 2000.

But Asia-Pacific Economic Cooperation has never become a serious decision-making body. It has only once been the stage for significant negotiations - in the wake of the Asian financial crisis in the late 1990's. At that time, the assembled leaders agreed to steps to prevent future economic failures from rippling through the world financial system. Some of the provisions were adopted; others forgotten and never mentioned in follow-up meetings.

On Sunday, the leaders announced some modest goals in liberalizing trade but made no assessment of their progress toward a goal set in the 1990's: completely free trade among developed nations by 2010, and among the developing nations by 2020. An accord on controlling portable, shoulder-fired missiles, a huge threat to commercial aircraft, largely repeated goals the group set last year. An agreement on fighting corruption echoed an accord from several years ago.

The first sign of social misunderstanding between the United States and Chile came Saturday night, when Chilean security agents initially prevented Mr. Bush's lead agent from following him into a dinner for heads of state attending the conference. When Mr. Bush noticed the commotion, he walked back outside, reached into a group of scuffling guards, grabbed his lead agent by the suit and pulled him out of the melee. Mr. Bush then shook his head, as if in disbelief, and escorted the agent into the dinner.

In a videotape of the incident, which played over and over throughout the region on Sunday, it appears as if Chilean security officials tried to restrain Mr. Bush before they recognized him - perhaps thinking he was another member of the Secret Service detail. One of Mr. Bush's aides said that the president had been alerted before the incident that there was some disagreement with the Chileans about whether the detail would be allowed to enter the dinner.

Security for the 21-nation conference is being provided by the Chilean national police, who have been widely criticized by human rights groups here and abroad for heavy-handed tactics, during the military dictatorship of Gen. Augusto Pinochet and under democratic rule. On Friday, the police used water cannons and tear gas to break up an anti-Bush street demonstration after a relatively small group of protesters threw rocks and bottles at them.

At the news conference here on Sunday afternoon, Mr. Lagos indirectly acknowledged the dispute, saying his government likes to receive foreign visitors "with the full honors they deserve," but minimized its importance. "We are going to have a work meeting, a news conference and then a working meal with President Bush, which is all that I would like to say about that in particular," he said.

The most important thing, the Chilean leader said, is not the social arrangements but to "gain the maximum advantage from a visit." When he last visited the United States in July, Mr. Lagos added, he followed the same format, that of a small working meal rather than an elaborate banquet.