The U.S. Senate has postponed a vote on the DREAM Act in order to introduce a version that already passed the House of Representatives.
It is not clear whether Democrats have the votes necessary to overcome a Republican-led procedural motion blocking consideration of the bill. The legislation would give young immigrants brought to the country illegally the chance to become citizens.
In a statement, President Barack Obama praised the passage in the House as "the right thing to do" for America. He says the bill would correct a flaw in the immigration system that punishes young people who have grown up in the United States and have already made contributions to their communities.
The measure faces stiff opposition from Republicans, who say it would encourage and reward illegal immigration.
The House approved the bill – known as the Development, Relief and Education of Alien Minors – in a vote of 216 to 198.
The measure would grant illegal immigrants brought to the U.S. while under the age of 16 the opportunity to gain legal residency – and ultimately citizenship – by going to college or serving in the U.S. military for two years.
Opponents say it gives illegal immigrants a fast-track to citizenship through college or the military, while immigrants who came to the United States legally do not have the same opportunity.