WASHINGTON (AP) — Business and labor groups announced agreement Thursday on the principles of a key priority for a comprehensive immigration bill: a new system to bring lower-skilled workers to the U.S.

The Chamber of Commerce and the AFL-CIO reached consensus after weeks of closed-doors negotiations they were conducting at the request of Sens. Charles Schumer, D-N.Y., and Lindsey Graham, R-S.C., two of the senators involved in crafting an immigration deal on Capitol Hill.

The principles include agreement on the need for a mechanism to let businesses more easily hire foreign workers when Americans aren't available to fill jobs. This will require a new kind of worker visa program that does not keep all workers in a permanent temporary status and responds as the U.S. economy grows and shrinks, the groups said in a joint news release.

They also said they see the need for a new professional bureau housed within a federal executive agency and tasked with informing Congress and the public about labor market needs and shortages. That addresses a key demand from the labor side for a more transparent and data-driven process about business' needs for workers.

But the joint statement from the Chamber and AFL-CIO made clear that more work needs to be done to finalize their deal so that it can be included in a comprehensive immigration package.

"We have found common ground in several important areas and have committed to continue to work together and with member of Congress to enact legislation that will solve our current problems in a lasting manner," the statement said.

"We are now in the middle — not the end — of this process."

Even so, Thursday's agreement represents a significant step in talks that some on Capitol Hill gave little chance of success, especially as the groups missed an informal Feb. 15 deadline for an agreement.

"This is yet another sign of progress, of bipartisanship, and we are encouraged by it," said White House press secretary Jay Carney.

President Barack Obama has been criticized by Sen. Marco Rubio, R-Fla., for failing to include a temporary worker program in his own immigration blueprint, and Carney would not say whether the White House supports a visa program for low-skill workers. But Carney said that the agreement between the two traditionally opposing sides in the debate "represents significant progress."

Business and labor have long been at odds over any temporary worker program, with business groups wanting more workers and labor groups concerned about worker protections and any large-scale program that could displace American workers. The issue helped sink the last congressional attempt at rewriting the nation's immigration laws, in 2007, which was partly why Schumer and Graham asked Chamber President Tom Donohue and AFL-CIO President Richard Trumka to try to forge an accord that Senate negotiators could include in legislation they are aiming to finalize by next month.

The Chamber and AFL-CIO have taken the lead in negotiations that have also included other business associations and labor unions.

The principles announced Thursday make clear that both sides have given ground. Business will get a temporary worker program, and labor will see creation of a government bureau that describes labor market needs, instead of letting employers themselves define their own needs.

The two sides also agreed that American workers "should have a first crack at available jobs," and to ensure that happens they said they are committed to improving the way information about job openings reaches workers, particularly in disadvantaged communities.

Various thorny issues remain to be addressed, including how many new visas would be provided under the new program and what kind of pay and protections workers would get.

The U.S. already has several temporary worker programs, but they're viewed as cumbersome and outdated, and experts say a large proportion of migrant workers in agricultural and other low-skill fields like landscaping or housekeeping are in the U.S. illegally. How to ensure that future workers come to the U.S. legally is the goal of the business-labor talks, and will be a key part of comprehensive immigration legislation that also will focus on securing the border and providing an ultimate pathway to citizenship for the 11 million illegal immigrants already in the U.S.

Eliseo Medina, secretary treasurer of the Service Employees International Union, which has been involved in the negotiations, said Thursday's announcement was great news.

"For the first time ever, business and labor have put down in writing, and publicly, our commitment to immigration reform," Medina said in a phone interview. "Given the commitment of the parties I actually feel optimistic that everyone's working in good faith and we can reach an agreement."

In 2007, comprehensive immigration legislation foundered after an amendment was added to end a temporary worker program after five years, threatening a key priority of the business community. The amendment passed by just one vote, 49-48. Obama, a senator at the time, joined in the narrow majority voting to end the program after five years.