Jackson, Miss. Mississippi's and Alabama's U.S. senators voted against an immigration bill that passed the chamber.
Republicans Thad Cochran and Roger Wicker of Mississippi, and Jeff Sessions and Richard Shelby of Alabama opposed the bill that passed Thursday, saying it's flawed.
Sessions led the opposition to the bill. he described it as "amnesty first" and said it lacks any assurance of enforcing border protections.
Shelby said there are many problems and questions surrounding the legislation.
It would still need to pass the U.S. House before it could become law.
Cochran says the legislation would not guarantee that U.S. borders will be truly secured or that people would stop entering the country illegally.
Wicker says the current immigration system is broken and he doesn't believe the bill would fix it.