An immigration bill endorsed by President Barack Obama easily cleared an important test on Monday when the U.S. Senate backed new border security steps seen as essential to the legislation's fate.
The border security amendment cleared a procedural hurdle by attracting more than the 60 votes needed, leaving opponents of the bill with few remaining opportunities for killing or further delaying passage of the legislation this week.
The bipartisan legislation would bring the biggest changes to U.S. immigration law since 1986, granting legal status to millions of undocumented foreigners who also would be put on a 13-year path to citizenship.
Last week, a small group of senators reached a deal on strengthening border security requirements of the bill by authorizing the hiring of 20,000 more law enforcement agents over the next 10 years and buying high-tech equipment to help stop illegal crossings at the U.S. border with Mexico.
The amendment, which is likely to be approved later this week now that the procedural block has been swept away, also calls for finishing construction of 700 miles (1,120 km) of border fence.
The steps were designed to attract more support for the bill from Republicans, who have been concerned that a "pathway to citizenship" for 11 million illegal immigrants would spark a new wave of unauthorized border crossings.
Republican Senator John Hoeven of North Dakota acknowledged that some members of his party in the House of Representatives have called for a more incremental approach to immigration reform than the Senate's comprehensive bill offered.
Hoeven helped write the border security amendment that could propel the immigration bill to a large bipartisan victory in the Senate later this week.
But Hoeven said, "We have tried to come up with something that is bipartisan so that it can move in the House. Hopefully it (the amendment) will encourage them to move forward."