Editor's note: This story has been updated to include comment from Marco Rubio.
LAS VEGAS — Firing back at Marco Rubio's campaign in an increasingly nasty dustup over their immigration views, Ted Cruz on Thursday maintained that he has never wavered in his position on people already in the country illegally.
"Let's have a moment of simple clarity: I oppose amnesty. I oppose citizenship. I oppose legalization for illegal aliens," the Texas senator told reporters before a rally in Las Vegas. "I always have and I always will, and I challenge every other Republican candidate to say the same thing or if not, to stop making silly assertions that their records and my records on immigration are the same. It is demonstrably false."
Cruz's remarks came two days after he and his campaign made clearer than ever that he does not support providing a form of legalization to the 11 million to 12 million people already in the country illegally. Cruz was repeatedly pressed on the issue during a debate Tuesday, and he spent the next day largely defending his involvement in immigration reform efforts two years ago.
Cruz reiterated Thursday that an amendment he proposed to the so-called Gang of Eight immigration bill, which Rubio authored, was a "poison pill" meant to undercut the legislation. Cruz's amendment would have stripped a path to citizenship out of the bill while keeping in place a path to legal status — a distinction Rubio's campaign has pounced on as it seeks to show the two senators are not all that different in their immigration positions.
"It's called calling their bluff," Cruz said of the amendment, adding that it "laid naked the partisanship and the hypocrisy and the lies of the Rubio-Schumer amnesty plan."
As Cruz was campaigning in Nevada, Rubio was stumping in Iowa, where he told reporters Cruz still was not being clear about his immigration views — especially after Cruz said during the debate he does "not intend to support legalization." Cruz campaign chairman Chad Sweet later told reporters the senator is "unequivocally" opposed to legalization.
"He's going to have a hard time because he's not told the truth about his position in the past on legalization," Rubio told reporters before a town hall in Muscatine. "And up until the debate, he had never said what he said."
On Thursday morning in Las Vegas, Cruz had his own take on why the debate was a turning point, pointing out how Rubio did not shy away from his leading role on the Gang of Eight bill, which included a path to citizenship.
"Tuesday was very interesting because Tuesday for the first time in five debates, Sen. Rubio publicly admitted not only did he support President Obama and Schumer's amnesty, but he still supports amnesty and citizenship today," Cruz told reporters. "He had avoided doing that in the first four debates. He explicitly admitted it in this last debate."
Cruz spoke to reporters before the first rally of a weeklong tour of nine mostly southern states.
Sean Sullivan of the Washington Post contributed to this story.