"They were like death, and un-American. Un-American. Somebody said, ‘Treasonous.' I mean, yeah, I guess why not," the president said during a Monday speech at a manufacturing plant in Cincinnati, Ohio, to promote tax cuts.
"Can we call that treason? Why not?" he added. "I mean they certainly didn't seem to love our country that much."
Trump also said that Democrats would prefer to see him "do badly than our country to do well," a behavior he called "very selfish."
— CSPAN (@cspan) February 5, 2018
"It got to a point where I really didn't even want to look too much during the speech over to that side, because honestly it was bad energy. No, it was bad energy," the president added.
Trump criticized US House of Representatives' Democratic Party leader Nancy Pelosi for calling the $1,000 bonuses with which some companies have rewarded their employees after Trump's recently passed tax overhaul "crumbs." He also referred to Pelosi as the Republicans' "secret weapon."
Last fall, Pelosi criticized Trump's tax cuts as favoring the rich. She said, "You've set a banquet for the wealthy and corporate America and thrown a few crumbs" to the middle class.
During his speech, Trump also appeared to take credit for the fact that no football players kneeled on Super Bowl Sunday during the national anthem.
"There was nobody kneeling at the beginning of the Super Bowl," Trump said, referring to the game between the New England Patriots and the Philadelphia Eagles. "We've made a lot of improvement, haven't we?"
Trump has repeatedly upbraided NFL players who kneel during the national anthem in protest of unfair police treatment of minorities, arguing that the gesture is disrespectful to the military.
As Trump made his speech on Monday, cable networks showed a falling Dow Jones industrial average. Ironically, Trump has repeatedly pointed to the rising stock market since he came into office as one of his great achievements.
The Dow ended up closing down 4.6 percent, and experiencing its most dramatic points drop during a single day in its history: at one point, the Dow had fallen 1,579 points, before recovering to close about 1,175 points lower than the previous day's trading.