LAS VEGAS — President Barack Obama proposed to rewrite U.S. immigration laws Tuesday, echoing a bipartisan group of influential U.S. senators in a one-two step that signaled a changing political landscape and the best chance in a generation to change the way the nation treats those who have arrived here illegally.

"The good news is that for the first time in many years, Republicans and Democrats seem ready to tackle this problem together," Obama told a diverse audience at a Las Vegas high school. "Members of both parties, in both chambers, are actively working on a solution. ... At this moment, it looks like there's a genuine desire to get this done soon, and that's very encouraging."

Many Republican leaders now support an immigration overhaul — even a pathway to citizenship — after a bruising election in which Latinos voted overwhelmingly for Obama over Republican Mitt Romney, though a battle remains in Congress.

The Senate will hold its first hearing Feb. 13. Legislation could be introduced by early March. If Congress is unable to move a timely proposal, Obama said, he will send his own and ask for a vote.

Some Republicans and Democrats agree on broad outlines of legislation that would allow the estimated 11 million who reside in the United States illegally to become citizens.

The president's package is similar to — but more aggressive than — a plan the eight senators unveiled Monday.

The senators are Democrats Richard Durbin of Illinois, Charles Schumer of New York, Robert Menendez of New Jersey, Michael Bennet of Colorado and Republicans Sen. Jeff Flake of Arizona, John McCain of Arizona, Lindsey Graham of South Carolina and Marco Rubio of Florida.

The biggest disagreement is over what the nation's illegal immigrants would need to do to become citizens.

"How long until they can become legal permanent residents? How long until they can be on a concrete path to citizenship?" asked Marshall Fitz, director of immigration policy at the Center for American Progress. "That is where there is a difference of opinion."

Under Obama's plan, those granted work permits likely would be able to apply soon for their green cards and then start the process of citizenship, according to Marielena Hincapie, executive director of the National Immigration Law Center. The White House did not specify how soon.

Under the Senate plan, it could take a decade or more before immigrants could get in line for citizenship.

Another potential obstacle: Obama would allow citizens and residents to seek a visa for their same-sex partner — a provision some Republicans oppose.

Both proposals would create a nationwide system to verify the legal status of workers, punish businesses that hire illegal immigrants, allow more highly skilled immigrants to stay in the country and increase border security.