New details emerged Friday about Sen. Bernie Sanders' infamous honeymoon in the Soviet Union back in the 1980s -- including an anecdote about how his America-bashing abroad prompted one of his traveling companions to walk out of the room.

“I got really upset and walked out,” David F. Kelley, a Republican who helped arrange the trip and was part of the entourage, recalled in an extensive piece in The Washington Post. Kelley said that during Sanders' 1988 trip, the now-2020 presidential hopeful acted inappropriately by criticizing his own country amid the Cold War.

“When you are a critic of your country, you can say anything you want on home soil," he said. "At that point, the Cold War wasn’t over, the arms race wasn’t over, and I just wasn’t comfortable with it.”

Sanders' criticism reportedly included knocking the cost of housing and health care in the U.S. while, at a banquet, blasting the U.S. for interventions in other countries.

During an hour-long news conference upon his return to the U.S., Sanders, a self-described democratic socialist, seemed unrepentant.

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“The fact that we were willing to be critical of the United States . . . I think that made them maybe more appreciative of our criticisms we made of their own society,” he said, according to the Post.

“We were saying, ‘Yeah, in our country, we also have a housing crisis. Our housing in general is better than yours, but people are paying 40 percent of their income for housing. The quality of your housing is not good, but we appreciate the fact that people are paying 5 percent. The quality of your health care is not good, but in the United States, believe me, we have enormous problems in terms of our health-care system.’”

The details are the latest to emerge from Sanders' past, as the Vermont senator establishes himself as perhaps the premier progressive among a vibrant insurgency within the Democratic Party. Sanders, along with others, have pushed big government policies like "Medicare-for-all" and free college tuition, which conservatives have derided as unrealistic and too expensive.

"I did not see a hungry child. I did not see any homeless people,” Sanders said after his visit to the Soviet Union. He's also praised the Soviet Union's transportation system and defended Cuban dictator Fidel Castro for his efforts at improving education and health care.

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"The revolution there is far deeper and more profound than I understood it to be. It really is a revolution in terms of values," he said of the Cuban revolution.

In 1985, Sanders visited Nicaragua and said he was "impressed" by socialist leader Daniel Ortega. Other videos have shown Sanders defending bread lines and recalling the excitement he felt about Castro's revolution.

"I was a kid ... and it just seemed right and appropriate that poor people were rising up against rather ugly rich people," he said of the revolution.

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Sanders faces a tough challenge from former Vice President Joe Biden, perceived as more of a moderate, for the 2020 Democratic presidential nomination -- part of a field of over 20 candidates.

While he has garnered significant support in the polls, he's also lagged behind Biden and faced criticism over some of his more unorthodox positions.