Miami ? Immigrants and their families gathered at rallies across the country Friday to push for changes to U.S. immigration policy, but as a swine flu outbreak continued to spread, attendance at some events was smaller than organizers had hoped.

Organizers sought to channel the political muscle Hispanics flexed last fall for Barack Obama into a new cause: jump-starting stalled efforts to forge a path to citizenship for the estimated 12 million illegal immigrants living in the United States.

They had hoped crowds would equal or exceed those of last year, which was down from 2006 when a stringent immigration bill poised to pass in Congress drew massive protests. But early reports suggested turnout would be far lower than in previous years.

Thousands were expected at events in Houston, Los Angeles, Milwaukee, Denver, Chicago, New York and other cities — mostly in the late afternoon, when workers finished their shifts.