The US House of Representatives approved a controversial measure on Wednesday providing a path to citizenship for illegal immigrants who came to the United States before age 16.
The "Dream Act" passed by 216-198 after sometimes heated debate. The Senate is scheduled to vote on Thursday on whether to begin debate on a slightly different version of the bill. It appears unlikely backers will win the 60 votes needed in the 100-member chamber to advance the measure.
The legislation would provide legal residency to undocumented young people who graduate from high school, complete two years of college or military service and have no criminal record.
The measure is backed by US president Barack Obama and Hispanic activists, who have been disappointed by Democrats' failure to deliver on Obama's promise of comprehensive immigration reform.
In a statement, Obama said, "This vote is not only the right thing to do for a group of talented young people who seek to serve a country they know as their own by continuing their education or serving in the military, but it is the right thing for the United States of America.
The bill is opposed by Republicans who slammed it as a "nightmare act."
"It is nothing more than mass amnesty that will undoubtedly encourage millions more to illegally immigrate into our country," Republican representative Dana Rohrabacher told the House.
In his presidential campaign in 2008, Obama pledged to push for an immigration overhaul, boosting border security and offering steps to legal status for many of the nearly 11 million illegal immigrants living in the United States. His administration and Congress have so far failed to agree on comprehensive measures.