Leaders from throughout the Americas will try to map out a common vision Monday on how to make the region safer, balancing concerns about security against alarm over increasingly aggressive U.S. measures to meet terror threats.

Governments from Mexico to Brazil have cried foul over U.S. measures to photograph and fingerprint visiting foreigners and to cancel airline flights over what some call dubious evidence of possible attacks.

But Latin American leaders excited about President Bush's proposal to allow their citizens to work in the United States may be hesitant to openly confront his policies during the two-day summit in this northern Mexico city.

Bush and most other leaders are scheduled to arrive Monday for private meetings before the formal start of the Special Summit of the Americas (search).

The Organization of American States (search), which includes all 35 nations in the hemisphere except Cuba, held its last summit in Quebec in April 2001 and had scheduled the next for 2005 in Argentina. But last year, Canada called for an interim meeting to deal with the regional repercussions of the Sept. 11 attacks.

"They thought that by bringing all of the heads of state together they could reframe the counterterrorism issues in a manner that would more effectively achieve hemispheric goals in free trade and democracy," said Robert Pastor, director of the center for North American Studies at American University in Washington.

Bush said this past week that one way to alleviate terror concerns would be to allow millions of migrants to work legally in the United States for at least three years and at the same time to crack down on illegal workers.

Latin American leaders responded with cautious optimism.

"It is a demonstration of collaboration, which we appreciate," Mexican President Vicente Fox (searchsaid Thursday. But he added: "We're going for more." Foreign Secretary Luis Ernesto Derbez indicated Mexico would lobby the U.S. Congress to pass Bush's plan.

Regardless of how it plays out, the mere idea of an immigration agreement provides a big political boost to both Bush and Fox.

For Bush, it will create an opportunity to improve relations with other nations in the region — a stance that could help his efforts to court Hispanic voters for the November elections.

A potential accord on migrant workers and the summit on Mexican soil could be a boon to Fox, who is trying to shake off the lame-duck status many have accorded him halfway through his six-year term. Under Mexican law, he can't run for re-election.

The Sept. 11 attacks had pushed aside negotiations on a migration accord, and relations between the United States and Mexico became strained after Fox's government refused to back the Iraq war.

Summit organizers said the leaders would attempt to reach consensus on fighting terrorism threats, but Latin American leaders are sure to bring complaints about what some see as heavy-handed U.S. tactics.

Mexican officials recently complained that Washington was pushing for cancellation of airline flights without providing hard evidence of security threats. Brazil reacted to the U.S. decision to fingerprint and photograph foreign visitors by doing the same to U.S. tourists.

New fears that terrorists are using Latin America as a staging ground as well as Bush's migrant proposal and the continuing debate over forming a Free Trade Area of the Americas are likely to overshadow other issues that some governments hope to address at the special summit.

Poverty, slow economic growth and political conflicts that are seen as potential threats to democracy were among the initial catalysts for holding an interim summit, and Latin American leaders have pushed for social issues to remain a top focus.

Secretary of State Colin Powell (searchsaid in a statement released Friday to Latin American news organizations that the "overarching aim" of the summit will be to set "practical goals that can rapidly improve the daily lives of people in the region."

Brazil has asked that the summit not take up the proposed Free Trade Area of the Americas, and Fox said Friday it wouldn't be on the official agenda. The free trade region is likely to be one of the main topics on the sidelines of the gathering, however.

The United States made its concerns over regional developments clear this past week. It alleged Cuba and Venezuela are working together to oppose pro-U.S. governments, including in Ecuador, Uruguay and possibly Bolivia, which just ousted an elected, pro-American president.

Roger Noriega (search), a U.S. assistant secretary of state, also voiced concern over Argentina's warming relationship with Cuba, saying the failure of Foreign Minister Rafael Bielsa (searchto meet with Cuban dissidents during a recent visit to Havana was "particularly disappointing." Argentine officials called the comments "impertinent" and "annoying."