The Senate authors of a far-reaching immigration bill have turned back GOP efforts to rewrite provisions allowing more high-tech workers into the country.

Amendments proposed by Republican Sen. Chuck Grassley of Iowa would have put more requirements on high-tech companies seeking to bring foreign workers to the U.S. on visas. An amendment by Sen. Ted Cruz of Texas would have allowed many more workers into the country than the bill contemplates.

Supporters argued any of the changes could have jeopardized support for the overall bill by undoing one of the carefully crafted compromises at its heart.

The votes came as the Senate Judiciary Committee met Tuesday for its second day of consideration of hundreds of amendments to a bipartisan immigration bill.

THIS IS A BREAKING NEWS UPDATE. Check back soon for further information. AP's earlier story is below.

Senators weighing a landmark immigration bill defeated an effort by Republicans Tuesday to require biometric identification _ such as fingerprinting _ to track who is entering and leaving the country.

The amendment by Sen. Jeff Sessions, R-Ala., would have required a biometric system to be in place before any immigrant here illegally could obtain permanent residency or citizenship.

"This is a big, big hole in the system and it's gone on for years and years," Sessions said as the Senate Judiciary Committee opened its second day of meetings to plow through hundreds of amendments to legislation remaking the U.S. immigration system, a top priority for President Barack Obama.

"This is one of the reasons the American people have so little confidence in any of the promises we make," Sessions said.

An author of the bill, Republican Sen. Lindsey Graham of South Carolina, agreed with Sessions that biometric IDs are the most secure. But he said authors of the bill determined they were too costly to implement anytime soon. Indeed current law already requires such a system to be in place, but the Department of Homeland Security has been unable to implement it.

Instead the bill seeks electronic scanning of photo IDs.

"Current law is a concept, and there is apparently not a whole lot of will by Republicans or Democrats to make the concept a reality," Graham said. "What we've done is taken the current system and make it better."

Sen. Chuck Schumer, D-N.Y., said a biometric system would cost $25 billion. He and other Democrats said Sessions' amendment would simply throw up barriers to a path to citizenship for the 11 million immigrants already in the country illegally.

The Senate Judiciary Committee voted 12 to 6 to defeat Sessions' amendment. Graham and Sen. Jeff Flake, R-Ariz., joined with the Democrats on the committee in voting it down.

Graham, Flake, Schumer and Sen. Dick Durbin, D-Ill., are four of the eight authors of the immigration bill. Since they sit on the Judiciary Committee together they have resolved to vote together against amendments that could strike at the core provisions of the legislation and threaten the fragile alliances behind it.

An author of the bill who's not on the Judiciary Committee, Sen. Marco Rubio, R-Fla., said through a spokesman that he was disappointed in the outcome of the amendment and planned to push as the bill moves forward to add biometric screening into the legislation. Rubio is working to sell the bill to fellow conservatives, and is hearing complaints that it is too soft on border security. He's said those aspects of the bill need to improve or it is unlikely to pass Congress.

The committee also voted 17-1 to defeat an amendment by Sessions to greatly curb new legal immigration programs under the bill, which creates a new visa for lower-skilled workers and also allows many more high-tech workers into the country. An amendment by Sen. Chuck Grassley, R-Iowa, to require additional information on job openings to be posted on the Labor Department website before an employer can hire a foreign worker on a high-tech visa passed by voice vote.