MSNBC’s “Morning Joe” hosts Joe Scarborough and Mika Brzezinski said Monday it was “un-American” for the Washington Nationals crowd to chant “lock him up” when President Trump was seen attending the World Series.

Trump was shown on the ballpark’s video screen Sunday night during Game 5 of the World Series between the hometown Nationals and visiting Houston Astros. Some fans greeted him with a crescendo of boos, while others mockingly yelled “lock him up.”

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Scarborough, an outspoken Trump critic, condemned the chant but was quick to remind viewers that the mantra originated with Trump supporters in 2016 against his opponent, Democratic nominee Hillary Clinton.

“It’s un-American, it started with Donald Trump. He’s made it the centerpiece of his campaign rallies,” Scarborough said.

“We find it sickening when it happens at his rallies,” Brzezinski said. “I find it kind of sickening to watch people leering at the president.”

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Scarborough said “of course it’s sickening” before explaining why he objects to “lock him up” chants.

“We are Americans and we do not do that. We do not want the world hearing us chant ‘lock him up’ to this president or to any president,” Scarborough said. “Let’s hope, as we move forward this is one less fascist tactic he and his supporters use during chants.”

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Scarborough and his wife/co-host Brzezinski were close to Trump and allowed him to regularly call in to “Morning Joe” before they turned on him when it became clear he had a legitimate shot at being the GOP nominee. They have since attacked Trump on a regular basis, and the president has taken personal jabs at the liberal power couple as well.

Fox News’ Jack Durschlag contributed to this report.