WASHINGTON - A last-minute dispute over wages for lower-skilled workers flared Friday as senators scrambled to sketch out a deal on a sweeping immigration bill before Congress takes a two-week recess.

The public clash between the U.S. Chamber of Commerce and the AFL-CIO underscored the high stakes involved in legislation that would dramatically reshape the U.S. immigration and employment landscape, putting 11 million illegal immigrants on a path to citizenship while allowing tens of thousands of new high- and low-skilled workers into the country.

The chamber and AFL-CIO, negotiating through the so-called Gang of Eight senators, had reached significant agreement on a new visa program to bring up to 200,000 lower-skilled workers a year to the country. The number of visas would fluctuate according to demand, and the workers would be able to change jobs and could seek permanent residency.

But the AFL-CIO was pushing for higher wages for the workers than the chamber had agreed to so far.

The dispute remained unsettled into the night, with chamber officials finally saying talks seemed to have stalled. Senators hoped to keep the disagreement from derailing negotiations on the overall bill.

The eight senators in the negotiating group, including Sens. Chuck Schumer, D-N.Y., and John McCain, R-Ariz., were aiming to finalize as many details as possible before leaving town so that the recess could be devoted to drafting the legislation, which would then be made public when the lawmakers return in April.

"We're close," Sen. Jeff Flake, R-Ariz., another member of the group, said after one round of meetings Friday. "The biggest issue has always been the future flow" of workers. Flake said there were only "a few minor items" left to deal with apart from the Chamber of Commerce-AFL-CIO matter.

If that can't be resolved in a way the two sides can agree to, the expectation is that the senators would come to their own agreement on the issue and include it in the bill, and hope the chamber and AFL can live with it or modify it as the bill moves through committee and Senate floor action.

The AFL-CIO argued that the Chamber of Commerce was trying to pay below median wage for any given group of workers, but the chamber said it would pay about the same as American workers get.

In the case of housekeepers, for example, the chamber proposal would mean $8.44 per hour, which falls below the federal poverty level for a family of four, while the AFL-CIO position was $11.39 per hour.

The new visas would cover dozens of professions such as long-term care workers and hotel and hospitality employees. Currently there's no good way for employers to bring many such workers to the U.S.; an existing visa program for low-wage nonagricultural workers is capped at 66,000 per year and is supposed to apply only to seasonal or temporary jobs.

As the day wore on, senators met hour after hour in a private chamber just off the Senate floor, and the chamber and AFL-CIO traded jabs, each accusing the other side of imperiling negotiations.

A proposal from the Gang of Eight that would divide the workers into three wage categories - two of them beneath median wage - was rejected by the AFL as insufficient, said Ana Avendano, assistant to the AFL-CIO president for immigration and community action. Avendano said the AFL proposed language stipulating that the new visas only should be used when employing foreign workers would not hurt wages and working conditions of U.S. workers, but that Republicans rejected that.

"It's shocking to us that the Republicans are willing to hold up the bill and they're saying that this bill is not moving forward without poverty level wages," Avendano said. "So we're hopeful that they will see the light and recognize how important this issue is and agree to move forward."

Randy Johnson, the chamber's senior vice president for labor, immigration and employee benefits, said the chamber simply wanted to stick with current law requiring that temporary workers be paid whichever is greater: what comparable American workers make or the prevailing wage as determined by the Labor Department.

"The unions have jeopardized the entire immigration reform effort, which would provide a pathway to legalization and citizenship for the 10-11 million undocumented workers, because of their refusal to take a responsible stance on a small temporary worker program," Johnson said in a statement.

McCain said the last-minute scuffle was understandable.

"People have a lot at stake here, this is a huge deal. We're talking about the lives of 11 million people just to start with, so I understand why passions are high and sentiments are high," McCain told reporters Friday.

"We just make steady progress," he said. "We take two steps forward, and then we take a step back."

A separate visa program for agricultural workers also remained unsettled but was not exciting as much concern.

McCain and Flake plan to visit the Arizona border next Wednesday with Schumer and Sen. Michael Bennet, D-Colo., another Gang of Eight member, to inspect conditions there as they finalize their bill. The legislation would impose new border security requirements before any path to citizenship could begin, which is critical to Republicans in the group.