Story highlights Donald Trump's campaign manager says he isn't buying Texas Sen. Ted Cruz's effort to run to the right of Trump on immigration

Corey Lewandowski said it's Trump's focus on immigration that has elevated the issue in the 2016 race

Washington (CNN) Donald Trump's campaign manager says he isn't buying Texas Sen. Ted Cruz's effort to run to the right of Trump on immigration.

Corey Lewandowski said he doesn't believe Cruz was sincere when he said Monday that he'd not only, like Trump, boot undocumented immigrants out of the United States -- he'd also prevent them from re-entering the country legally.

"I find it very difficult to believe that Sen. Cruz is not going to allow individuals to come back into the country legally," said Lewandowski In an interview with CNN's Jake Tapper on "The Lead" Tuesday.

Trump has said he'd build a wall on the U.S.-Mexico border and eject more than 11 million undocumented immigrants from the United States. But he's said he'd allow those who have followed U.S. laws back into the country through an expedited process.

Lewandowski said it's Trump's focus on immigration that has elevated the issue in the 2016 race.

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