Fox News' Sandra Smith, in off-camera clip, reacts to guest's election comment: 'What is happening?'

Fox News anchor Sandra Smith has become the subject of Twitter buzz after a now-viral clip showed her off-camera reaction to the comments of a guest during the network's Saturday broadcast.

In the video circulating on social media, Smith squinted her eyes and shook her head while DC-based lawyer Cleta Mitchell said "just because CNN says — or even Fox News says — that's somebody's president, doesn't make them president."

Major networks such as CNN, the Associated Press as well as Fox News reported Democratic nominee Joe Biden surpassed 270 electoral votes and secured the race for president Saturday after Pennsylvania was finally called for the former vice president.

Smith, whose microphone was still on, responded to Mitchell's comments with incredulity.

“What? What is happening? Trace, we’ve called it," she says to her co-anchor, Trace Gallagher, who didn't respond in the moment.

Fox News: cuts away from Trump campaign news conference

When reached for comment, Mitchell directed USA TODAY to a tweet she posted on the topic.

"Sandra Smith thinks Fox News calling the election means Biden is President. Forget that pesky Constitution... happy to be considered a nut job because I believe in the rule of law," she wrote on Monday alongside the viral clip.

Fox News declined to comment.

On Monday, meanwhile, Fox News' Neil Cavuto broke into coverage of Kayleigh McEnany's Trump campaign news conference Monday and abruptly pulled the plug following unsubstantiated and "explosive" claims of voter fraud.

White House press secretary McEnany, a federal employee speaking in a "personal capacity" as a Trump campaign adviser and spokesperson, was explaining President Donald Trump's refusal to concede election.

Shortly after McEnany's claim that the Democratic Party was "welcoming fraud" and "welcoming illegal voting," Cavuto appeared at his desk on Fox's split screen and stopped the network's live coverage.

'FRAUD' FACT CHECKS:

• No evidence that 14,000 dead people voted in Michigan

• Ballots in video of "Trump ballots" being burned is fake, city officials say

• Nine military ballots were incorrectly discarded, but it wasn't an instance of fraud —and they weren't in a ditch

• Arizona election department: Sharpies can be used on ballots

"Whoa, whoa, whoa, I just think we have to be very clear," Cavuto said, referring to McEnany's statements. "She's charging the other side is welcoming fraud and welcoming illegal voting. Unless she has more details to back that up, I can't in good countenance continue showing you this."

Contributing: Kelly Lawler, Bryan Alexander

This article originally appeared on USA TODAY: Fox News' Sandra Smith, in viral clip shows, disbelief at guest claim