By JIM AVILA and JORDAN FABIAN

A bipartisan group of senators plans to introduce its long-awaited immigration bill on Tuesday, Senate sources confirmed to ABC News.

Four Democrats and four Republicans, known as the "Gang of Eight," wrapped up months of hard-fought negotiations this week and will put forth a bill that includes a pathway to citizenship for many of the 11 million undocumented immigrants living in the U.S.

But the legislation includes a cutoff date of December 2011, which would bar undocumented immigrants who arrived in the U.S. after then from seeking legal status and then citizenship, according to sources.

Sources who spoke to ABC News said that the cutoff date was a Republican-backed idea designed to only allow those undocumented immigrants already assimilated into their communities to stay. But that idea may run into resistance from Democrats and immigrant-rights groups since it may exclude many undocumented immigrants from obtaining legal status.

"All issues that rise to the member level have been dealt with," Sen. Chuck Schumer, D-N.Y. said in a statement on Thursday. "All that is left is the drafting."

The bill would also provide for increased border security and interior enforcement against employers who knowingly hire undocumented immigrants. The Senate plan would call for surveillance of 100 percent of the U.S.-Mexico border and 90 percent effectiveness in catching people trying to illegally enter the U.S., the Associated Press reported.

Certain border security metrics would need to be met before undocumented immigrants granted provisional legal status could apply for permanent status, and then citizenship. That's a process that could last 15 years, according to media reports. The bill would also require employers to verify the immigration status of job applicants.

A secret "Gang of Eight" in the House of Representatives is working on its own immigration bill. According to House sources, members of the "Gang" will continue to meet daily next week to produce their own bill. That legislation would prevent undocumented immigrants who arrived after January 2011 to apply for legalization.