Updated

The immigration reform legislation could be released in the Senate as early as Thursday, followed by a weeks of debate and amendments, a congressional aide told Fox News on Tuesday.

A bipartisan group of senators has been working on the legislation since early January.

Members had a major breakthrough last month when the AFL-CIO and the Chamber of Commerce agreed on a plan for work visas for low-skilled laborers. However, the group still faces other hurdles before reaching an agreement, including determining to what extent U.S. borders must be secured before creating a path to citizenship for illegal immigrants. There are roughly 11 million illegal immigrants in the United States.

The extended process, the aide said, was intended to win support from Florida Republican Sen. Marco Rubio, a key member of the so-called Gang of Eight senators.

Rubio has called for an extended debate and amendment process after the legislation is introduced in the Senate Judiciary Committee to allow related parties to have their say.

The aide said the senators had a good discussion Tuesday with committee Chairman Sen. Patrick Leahy, D-Vt.

“We are optimistic that we will be able to introduce legislation soon,” the aide said. “Chairman Leahy has agreed to hold a hearing as soon as possible after the legislation is introduced and has promised to have unlimited debate and amendments during the committee mark-up.”

Rubio spokesman Alex Conant said the senator “has said from the outset that we will not rush this process, and that begins at the committee level. … It’s good that senators and the public will have weeks to study this proposal.”