Millions of undocumented immigrants in the U.S. should be allowed to earn their citizenship because deporting them isn't realistic, Florida Republican Sen. Marco Rubio said Sunday.

Rubio, who has emerged as a leading supporter of revamping U.S. immigration laws, spoke on all five nationwide Sunday talk shows to defend a bipartisan proposal that is expected to be introduced this week.

On NBC's "Meet the Press" program, Rubio rejected arguments that the proposal would amount to amnesty for the estimated 11 million undocumented immigrants in the U.S.

"It's not amnesty, because you pay serious consequences for having violated the law," Rubio said. "If someone believes we can round them up and deport them, they should advocate that. I don't think that's a reasonable goal."

The plan would allow undocumented immigrants to remain and work in the country if they meet certain requirements and apply for permanent residency — or a green card — after 10 years, Rubio said. They could apply for citizenship after receiving their green cards, he said.

A group of eight senators has resolved "every significant disagreement" when it comes to immigration reform and planned to introduce a bill Monday, said Sen. Charles Schumer, a Democrat from New York.

"I think you'll see a major agreement, that's balanced but fair, that will have the widespread support of the American people," Schumer said Saturday. "This is a balanced approach that both prevents future waves of illegal immigration, but has common-sense solutions."