Another bombshell has landed on Donald Trump's presidential run from Newsweek, which in a story released Thursday alleges the billionaire businessman broke U.S. law by doing business with Cuba.

The alleged dealings took place in the 1990s, when a U.S. trade embargo against the communist country made it illegal for any American to invest even a single dollar in the Cuban economy.

The story by investigative reporter Kurt Eichenwald — citing former Trump executives, court filings and internal company papers — says a company controlled by Trump spent at least $68,000 on a 1998 foray into Cuba.

Trump executives allegedly hired an outfit called Seven Arrows Investment, which went to Cuba and investigated possible business opportunities for Trump's company, which was known at the time as Trump Hotels & Resort Casinos.

Seven Arrows then told Trump executives how to obscure any dealings in Cuba by linking the money to a false charity, the Newsweek report alleges.

If true, such dealings would undermine the Republican candidate's past and present tough talk on Cuba and the regime of longtime president Fidel Castro and his successor, Raul Castro.

Trump has slammed Cuba's Fidel Casto, seen here in 2014, at recent campaign events and during an earlier run at the White House in 1999. (Alex Castro/Associated Press)

Trump touted embargo

Trump vowed to "stand with the Cuban people in their fight against Communist oppression" two weeks ago in an address to supporters in Florida, where anti-Castro sentiment is strong.

The candidate went on to describe the recent warming of U.S.-Cuba relations under President Barack Obama as "a one-sided deal for Cuba that … benefits only the Castro regime."

Newsweek noted that during Trump's previous run at the White House in 1999 he told another crowd in Florida that the embargo "must stand."

"Putting money and investing money in Cuba right now doesn't go to the people of Cuba," he said. "It goes to Fidel Castro."

Newsweek earlier this month published a lengthy examination of Trump's overseas dealings, alleging his business deals around the world would "make it impossible" for him to conduct foreign policy "without padding or depleting his wallet."

Trump held a campaign event in New Hampshire Thursday afternoon and denied the story on local television.

Trump told New Hampshire's NH1 News he "never did business in Cuba."

He added, "No, I never did anything in Cuba. I never did a deal in Cuba."

Trump is slamming Newsweek's reporter, saying he has a "bad reputation."