President Barack Obama on Monday renewed pressure on congressional negotiators to deliver on an immigration overhaul.

“We’ve got a lot of white papers and studies. We’ve just got at this point to work up the political courage to do what needs to be done,” Obama said during an address at a naturalization ceremony for 28 new Americans. “I expect a bill to be put forward. I expect the debate to begin next month and I want to sign that bill into law as soon as possible.”

Bipartisan groups in the House and the Senate have been meeting for weeks to craft comprehensive immigration legislation. At first, both groups said they hoped to release their measures late this month, but that deadline has slipped to next month.

In the Senate, negotiators had hoped to mark up an immigration bill in the Judiciary Committee in early April. But Patrick J. Leahy, D-Vt., said that deadline would be pushed back a few weeks while senators have a chance to digest the bill once it is released. The bill is likely to be bulky, addressing all facets of the country’s complex immigration laws.

Leahy has promised not to rush the bill to the floor.

“Because we do not yet have legislative language to debate, the Senate Judiciary Committee will not be able to report a comprehensive immigration bill by the end of April, which was my goal,” Leahy said in a statement in which he also chided Senate negotiators for missing their March deadline.

By contrast, Republicans on the committee want to slow the process. Six of the committee’s eight Republicans sent Leahy a letter last week urging him to postpone the markup until members have a chance to hold more hearings and debate the measure.

“We believe that hearings are necessary to examine implementation of the components essential to a workable system, especially given that 43 current members of the Senate were not here during the last debate in 2007,” they wrote.

The Republicans’ request could postpone the bill’s ultimate adoption for months or years, a scenario Obama on Monday made clear was unacceptable.

In his address, Obama laid out his priorities for immigration legislation, priorities that align closely with a set of principles that the Senate group put out in January.

Obama said he intended the overhaul to strengthen border security and punish employers who knowingly hire undocumented immigrants, two priorities for Republicans. But he also said the bill would have to include “a responsible pathway to earned citizenship for the 11 million undocumented immigrants who are currently living in the shadows.”

The legal immigration process also needs to be rewritten, he said, “so that our citizens don’t have to wait years before their loved ones are able to join them in America and so that we’re attracting the highly skilled entrepreneurs and engineers that are going to help create good-paying jobs and grow our economy.”

“Let’s get this done,” Obama said. “And let’s do it in a way that keeps faith with our history and our values.”