MEXICO CITY (AP) – The chances that the U.S. Congress will overhaul immigration rules have increased with the end of the political season and the improvement of security along the U.S.-Mexican border, Secretary of State Colin Powell said Tuesday in Mexico.

But Powell cautioned that approval of the first major immigration changes in 18 years would depend on the new Congress that will take office in January.

“We don’t want to overpromise,” Powell told a news conference during discussions here on a broad range of cross-border issues. Joining Powell for his 20-hour stay in Mexico were five fellow Cabinet secretaries.

Powell met with Mexican President Vicente Fox, who has made migration reform in the United States a top foreign policy priority. Fox says the millions of Mexicans who work in the United States should have legal status there so they can live without fear of arrest and deportation.

During his discussions, Powell said he reaffirmed President Bush’s “plan to work with our new Congress to develop a temporary worker program to match willing foreign workers with willing U.S. employers.”

The comments suggested the Bush administration was giving priority to the provision in Bush’s proposal that would give workers who still live in their home countries permission to work in the United States if they have a job offer.

A more controversial provision – which Powell did not mention – would allow undocumented aliens already in the United States to achieve legal status if they can prove they have employment. Beneficiaries could to stay in the United States for three years, then be permitted to remain longer if certain conditions are met.

Many in Congress view Mexicans and others who entered the United States without official permission as lawbreakers, and are wary of doing them any favors. Mexicans constitute by far the largest illegal immigrant community, estimated to total about 10 million.

Bush and Fox agreed in 2001 to press for immigration reform, but the Sept. 11 terrorist attacks soured Congress on the idea. Since the attacks, enhanced border security has been the dominant U.S. goal in relations with Mexico.

Powell indicated he is pleased with Mexican cooperation on that issue.

“We are coming out of the 9/11 period and doing a better job of securing our border,” he said. He also suggested Congress may be freer to act next year, mindful that no member faces an election until 2006.

Fox said the time is ripe for an immigration accord. “We have done all the analysis, diagnostics and problem solving possible,” Fox said in a radio interview Monday. “There’s no reason to lose much time.”

Powell made his rounds on a warm sunny day amid signs that U.S.-Mexican relations are on a reasonably sound footing. Plans are under way for Mexico to honor Bush with a state visit next year, reciprocating a September 2001 state visit Fox made to Washington.

Among other issues, Powell and his delegation discussed Mexico’s concerns about treatment of Mexicans on U.S. soil. Mexican Foreign Secretary Luis Ernesto Derbez, who joined Powell at the news conference, said that issue is “a permanent concern” of the two governments.

Relations were at a low point last year because of differences over U.S. policy in Iraq and decisions by American courts to carry out the death sentence against Mexican citizens without regard for international legal norms that require consular access to the accused.