Transportation Secretary Sean Duffy insisted that millions of demonstrators who take part in the peaceful No Kings protests are "part of antifa," which has been designated as a domestic terrorist organization by President Donald Trump.

Duffy made the remarks on Monday while complaining about air traffic controllers who call in sick during the government shutdown.

"Why do they want to create pain in my life? What, for political power?" the Trump official told Fox Business host Maria Bartiromo. "I think Americans are upset about that."

"But again, the No King's protest, Maria, really frustrating," he continued. "I mean, this is part of antifa, paid protesters. It begs the question, who's funding it?"

"But yeah, Democrats want to wait for a big rally of a No King's protest."

Duffy speculated that No Kings protesters or Rep. Alexandria Ocasio-Cortez (D-NY) could be behind the government shutdown.

"Chuck Schumer's not running the show," he said. "The No King's protesters or organizers are running the show. Is AOC threatening in a primary against Chuck Schumer? Is she running the show?"

"Chuck Schumer is blowing in the breeze," he added. "He has no power, no authority, because he's given it up to his primary opponent, potentially in AOC, or to the No King's protest organizers. And it's shameful."

In September, Trump signed an executive order designating antifa, an informal movement, as a domestic terrorist organization.