Updated

President Obama challenged Congress Monday to "finish the job" of finalizing legislation aimed at overhauling the nation's immigration system.

With members of the House and Senate away on spring break, Obama made his most substantive remarks on the difficult issue in more than a month, saying he expects lawmakers to take up debate on a quickly and that he hopes to sign it into law as soon as possible.

"We've known for years that our immigration system is broken," the president said at a citizenship ceremony at the White House. "After avoiding the problem for years, the time has come to fix it once and for all."

The president spoke at a ceremony for 28 people from more than two dozen countries, including Afghanistan, China and Mexico. Thirteen of the new citizens are active duty service members in the U.S. military. The oath of allegiance was administered by Homeland Security Secretary Janet Napolitano.

While Obama has hosted citizenship ceremonies in previous years, Monday's event was laced with politics, given the ongoing debate over immigration reform on Capitol Hill. A bipartisan group of eight senators is close to finishing draft work on a bill that would dramatically reshape the U.S. immigration and employment landscape, putting 11 million illegal immigrants on a path to citizenship. The measure also would allow tens of thousands of new high- and low-skilled workers into the country.

The president applauded the congressional effort so far, but pressed lawmakers to wrap up their discussions quickly.

"We've got a lot of white papers and studies," Obama said. "We've just got to, at this point, work up the political courage to do what's required."

Immigration shot to the forefront of Obama's domestic agenda following the November election. Hispanics made up 10 percent of the electorate and overwhelmingly backed Obama, in part because of the tough stance on immigration that Republicans took during the campaign.

The election results spurred Republicans to tackle immigration reform for the first time since 2007 in an effort to increase the party's appeal to Hispanics and keep the GOP competitive in national elections.

Obama and the bipartisan Senate group are in lockstep on the key principles of a potential immigration bill, including a pathway to citizenship, strengthening the legal immigration system, and cracking down on businesses that employ illegal immigrants. The White House has largely backed the Senate process, but says it has its own immigration bill ready if the debate on Capitol Hill stalls.