Story highlights 'Gang of Eight' senators have reached deal on major provisions, tweaking plan

Common ground found on wages and visas for undocumented farm workers

Negotiations result in deal regarding undocumented agricultural workers

Senators to formally propose bill on Tuesday with hearing set for the next day

The bipartisan "Gang of Eight" senators crafting a deal on comprehensive immigration reform, having reached an agreement on all of the major issues, is set to unveil its plan on Tuesday, sources with knowledge of the matter said.

While some small details still need to be ironed out, negotiators within and outside the group were able to find common ground on one of the last significant hurdles -- wages and visas for undocumented farm workers.

"After months of negotiation, I can announce that a bipartisan agreement has been reached addressing key issues of agricultural workers in the forthcoming comprehensive immigration reform bill," Sen. Dianne Feinstein, D-California, wrote in a statement on Friday.

The agreement "resolves outstanding issues including wage levels, agricultural guest worker visas and protections for U.S. workers," Feinstein said.

Hatch said the agreement "balances America's farming needs and the needs of both American and immigrant farm workers."

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But he said cautioned that he wasn't yet signing on to the full "Gang of Eight" plan.

Generally speaking, agricultural businesses back more visas and lower wages. Labor groups typically support fewer visas and higher wages.

The four Democrats and four Republicans responsible for assembling the overall "Gang of Eight" plan are on track to unveil the sweeping measure next Tuesday, the sources said.

Members of the Senate Judiciary Committee will hold their first public hearing on the legislation on Wednesday, followed most likely by committee markups in May and consideration by the full Senate in June, according to the sources.

Among other things, the eight senators have reached agreement on a path to citizenship that could affect up to roughly 11 million undocumented residents, as well as the creation of a system to assess the state of border security.

Specifically, the senators have agreed to a 13-year path to citizenship. It would take 10 years for undocumented workers to get a green card, and then another three years to gain citizenship.

Along the way, undocumented workers would have to pay a fine and back taxes, and pass a background check. The size of the fine remains unclear.

No undocumented worker would be eligible for citizenship until the border is considered secure -- a key sticking point for conservatives.

To measure border security, a commission would be created with the task of establishing and assessing a set of quantifiable criteria. The commission would be made up of officials named by state and federal leaders.

Several key Senate conservatives remain convinced that the emerging plan will be tantamount to amnesty for people who initially entered or have remained in the United States illegally.

"It is likely millions of current and future illegal immigrants ... will benefit from this amnesty," Sen. Jeff Sessions, R-Alabama, said Friday in a written statement.

The "Gang of Eight" includes Sen. Michael Bennet, R-Colorado, Sen. Marco Rubio, R-Florida, Sen. Lindsey Graham, R-South Carolina; Sen. John McCain, R-Arizona; Sen. Jeff Flake, R-Arizona; Sen. Robert Menendez, D-New Jersey; Sen. Dick Durbin, D-Illinois; and Sen. Chuck Schumer, D-New York.

Rubio and Bennet worked with non "Group of Eight" members Hatch and Feinstein on issues relating to undocumented farm workers.

Viewed as a potential Republican presidential candidate in 2016, Rubio will make full-court press on the issue on Sunday network talk shows, including CNN's "State of the Union" with Candy Crowley.

His aides say the round of appearances will not include any announcements, but should be viewed as his "opening argument" on immigration reform.

Democrats and Republicans in the House of Representatives, meanwhile, have been working on their own immigration overhaul plan.

Details of the House blueprint are not yet available. But Florida Rep. Mario Diaz-Balart, a key Republican in the House group, told CNN on Thursday that House negotiators have reached an agreement on the major issues, including border security and a pathway to citizenship.

The congressman declined to give any timeline regarding when a House bill would likely be introduced.