President Donald Trump tweeted Sunday morning that "Bernie Sanders was cut off" of CNN "for using the term fake news to describe the network" — but CNN quickly responded that Sanders had used the term jokingly, and that he had not been cut off.

"They said technical difficulties!" Trump tweeted.

In the interview, Sanders had been responding to a video clip of Trump saying that he had not heard reports that national security adviser Michael Flynn had spoken with Russia about sanctions before the inauguration.

Anchor Erin Burnett asked Sanders if he thought it was a "problem" that Trump was not familiar with the reports.

Sanders responded: "Well, I don't know. Maybe he was watching CNN fake news. What do you think?"

Before the feed cut out and the network broke for commercials, Sanders said, "That was a joke." In response, Burnett said, "I know it was a joke."

CNN responded to Trump's tweet with a transcript of the interview.