Sen. Marco Rubio said Thursday that he was "deeply concerned" about Donald Trump's business dealings in Cuba in 1998 during the U.S. embargo against Fidel Castro.
"This is something they’re going to have to give a response to," the Florida Republican told the ESPN/ABC "Capital Games" podcast, ABC News reports. "It was a violation of American law, if that's how it happened."
Newsweek reported Thursday that the presidential nominee conducted business illegally with Castro's Cuba as he called for the embargo on U.S. trade with the island nation to continue.
Trump did both while he sought the Reform Party's presidential nomination in 2000, according to the report.
According to documents quoted by writer Kurt Eichenwald, Trump's company spent at least $68,000 in 1998 on a consulting firm that sent executives to Cuba when spending "even a penny in Cuba was prohibited without government approval."
However, Newsmax contributor Mauricio Claver-Carone noted that "the Bill Clinton administration was licensing and encouraging U.S. companies to take scouting trips to Cuba, with the hope they would return and lobby Congress to ease the sanctions that he codified into law in 1996."
Similar efforts were being supported by the U.S. Chamber of Commerce, Claver-Carone said.
"I hope the Trump campaign is going to come forward and answer some questions about this," Rubio told the podcast. "Because if what the article says is true — and I’m not saying it is, we don’t know with a hundred percent certainty — I’d be deeply concerned about it."
Rubio, who quit the presidential campaign in April, endorsed Trump the following month.
The senator has long backed the Cuban embargo — and he opposed President Barack Obama's move to re-establish diplomatic ties with Havana in 2014.