Officials from 11 Latin American countries have agreed a co-ordinated lobbying campaign against a tougher immigration bill in the US.
The US wants tighter security along the Mexican border
At a meeting in Colombia they said they were concerned about the bill, being debated in the US Senate, and wanted jointly to promote Hispanic migration.
The US proposal backs a 1,130-km (700-mile) fence on the Mexican border.
Washington has accused Mexico of not doing enough to stem the flow of illegal immigrants into the US.
Correspondents say that every day an estimated 1,500 Latin Americans, mostly Mexicans, cross into the US illegally.
The 11 countries meeting in the seaside resort city of Cartagena were Mexico, the Central American nations, plus Colombia, Ecuador and the Dominican Republic.
Officials decided to send a mission to Washington next week to identify key US lawmakers on the immigration debate, Salvadoran Foreign Minister Francisco Lainez said.
Latin American governments would urge US legislators to change or defeat the bill that has already been passed by the US House of Representatives.
The lobbying campaign will use all diplomatic channels, as well as churches, charities and chambers of commerce, officials said.
President George W Bush has stressed that "border security must adapt to the nation's changing needs".
But Colombian Foreign Minister Carolina Barco said it was essential for Americans to understand how much Hispanic workers contributed to the economy.
The US bill also covers the use of troops and police to halt migrants, and tighter employment controls.