GOP White House front-runner Donald Trump this week seemed to cast doubt on rival Ted Cruz's eligibility to serve as president of the United States, noting that the Texas senator's foreign birth could lead to litigation.

"Republicans are going to have to ask themselves the question: 'Do we want a candidate who could be tied up in court for two years?' That'd be a big problem," the real estate tycoon said about Cruz, who was born in Calgary, Canada to an American mother and a Cuban father, The Washington Post reported.

Cruz renounced his Canadian citizenship in 2013, the Canadian Broadcasting Corporation reported. Most experts consider him a "natural-born U.S. citizen," which is one of the requirements Article II of the U.S. Constitution spells out to serve in the nation's highest office.

When the first Congress of the United States passed the Naturalization Act of 1790, it stipulated that children born abroad to U.S. citizens were natural born citizens too, Politifact noted. The Republican Party's 2008 presidential nominee, longtime Arizona Sen. John McCain, for instance, was born outside the United States while his father served in the Panama Canal Zone.

But Trump, who was also once among a number of critics casting doubts on President Barack Obama's birth records and citizenship status, suggested that Cruz would likely have to deal with the issue if he were elected to the White House.

"It'd be a very precarious one for Republicans because he'd be running and the courts may take a long time to make a decision. You don't want to be running and have that kind of thing over your head," Trump said.

"I'd hate to see something like that get in his way. But a lot of people are talking about it and I know that even some states are looking at it very strongly, the fact that he was born in Canada and he has had a double passport."

Cruz's renunciation of Canadian citizenship, however, means he is no longer eligible for that country's travel documents.

The Texas senator, for his part, took Trump's comments with humor, referencing an iconic episode of the sitcom "Happy Days."