Story highlights Rand Paul was echoing attacks started by GOP front-runner Donald Trump

Legal experts have said Cruz is a natural-born citizen because his mother was an American citizen

Washington (CNN) Sen. Ted Cruz's citizenship status could end up before the Supreme Court, Sen. Rand Paul said Monday, because it's still undecided if he qualifies as a "natural-born" American.

The Kentucky Republican hit his colleague and fellow presidential candidate on Fox News on Monday for being born in Canada and perhaps not fitting the constitutional requirement that a President be a natural-born citizen.

"Cruz is a natural-born Canadian," Paul said. "He was naturally born there. The question is, can you be natural-born Canadian and natural-born American at the same time? Maybe, but I think the courts will have to decide it, because it's never really been decided."

Paul was echoing attacks started by GOP front-runner Donald Trump, who has attacked the Texas senator over his citizenship status as Cruz has drawn closer to the billionaire businessman in the polls and overtaken him in Iowa.

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