Newsweek plans to release a story Thursday morning that Donald Trump did business illegally with Fidel Castro's Cuba even while calling on the embargo on U.S. trade with the island nation to continue as he sought the Reform Party's 2000 presidential nomination, MSNBC reports.

MSNBC's Rachel Maddow reported what she said were exclusive paragraphs from the story, and writer Kurt Eichenwald backed up the veracity of her claims on Twitter.

Story continues below video.

According to MSNBC, Eichenwald will report:

"A company controlled by Donald Trump, the Republican nominee for president, secretly conducted business in communist Cuba during Fidel Castro's presidency despite strict American trade bans that made such undertakings illegal. That's according to interviews with former Trump executives, internal company records and court filings."

Eichenwald writes that documents reveal Trump's company spent at least $68,000 in 1998 for company executives to visit Cuba at a time when spending "even a penny in Cuba was prohibited without government approval."

The company, with Trump's knowledge, ran the money through consulting firm Seven Arrows Investment and Development Corporation, according to the story.

"Once the business consultants traveled to Cuba and incurred the expenses for the venture, Seven Arrows instructed senior officers in Trump's company, then called Trump Hotels and Casino Resorts, on how to make the venture appear legal by linking it after the fact to a charitable effort," according to Newsweek.

The payment was made just before Trump – now the GOP nominee for president – made his first run at the White House by seeking the Reform Party nomination.

"On his first day of that campaign, he traveled to Miami where he spoke to a group of Cuban Americans, a critical voting bloc in the swing state of Florida," Newsweek reports.

"Trump vowed to maintain the embargo and never spend his or his companies' money in Cuba until Fidel Castro was removed from power. He did not disclose that seven months earlier Trump Hotels already had spent money sending consultants on the secret trip to conduct business in Havana."

MSNBC uncovered CSPAN footage of that speech, in which Trump told the group:

"As you know, and the people in this room know better than anyone, putting money and investing money in Cuba right now doesn't go to the people of Cuba; it goes into the pockets of Fidel Castro. He's a murderer, he's a killer, he's a bad guy in every respect, and frankly, the embargo against Cuba must stand if for no other reason than if it does stand he will come down."