Donald Trump on Sunday seized on Heidi Cruz's comment from a day earlier that her husband Ted Cruz is an immigrant.

"Heidi Cruz -- nice woman -- said 'My husband is an immigrant.' That's what I've been saying. I think she was trying to put a little bit of a Latin turn on it. He was born in Canada folks, he was born in Canada," the GOP presidential front-runner said at his second rally Sunday in Fort Wayne, Indiana.

At a campaign stop in Indiana on Saturday, Heidi Cruz said "Ted is an immigrant...He is Hispanic. We can unify this party."

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A Cruz aide told The Washington Examiner, however, that she misspoke and meant to call Cruz the son of an immigrant.

Trump in March retweeted an unflattering photo of Heidi Cruz, which compared her appearance unfavorably to his wife, former model Melania Trump. For awhile earlier this year, Trump questioned Cruz's eligibility for the presidency because he was born in Canada. He even threatened to take legal action, but said Sunday that Democrats "will bring a lawsuit against him." Cruz was born in Canada to an American mother and a Cuban father.

He first brought up Heidi Cruz's comments about her husband in an interview with Fox News' "Fox and Friends" on Sunday.

"I assume she's saying he's an immigrant from Canada. Because, you know, he lived in Canada for the first four years of his life. Not an immigrant, like I think she's referring to," he said in the interview.

This comes ahead of Tuesday's primary in Indiana, which could be critical in further winnowing the GOP presidential field.