Fox News is driving political violence in the US, a media watchdog warned, after the primetime host Tucker Carlson predicted “revolt” against the Biden administration.

In a Monday night monologue targeting the White House and military leaders over the US withdrawal from Afghanistan, Carlson demanded resignations. He also said: “When leaders refuse to hold themselves accountable over time, people revolt. That happens.

“We need to change course immediately and start acknowledging our mistakes. The people who made them need to start acknowledging them or else the consequences will be awful.”

Angelo Carusone, president and chief executive of Media Matters for America, a progressive group, said: “When there’s another big violent rightwing flashpoint that captures attention, way too many in media will wonder out loud: ‘How did this happen?’ ‘Were there the signs?’

“You don’t need to wade into the online fever-swamps to see the cauldron of extremism simmering. Fox News is ratcheting up heat and legitimising nightly.

“Fox News, not Facebook, will be the driver of the next insurrection. Plain and simple.”

Fox News declined to comment.

Misinformation spread through Facebook and other platforms has been widely blamed for stirring up political violence including the deadly assault on the US Capitol on 6 January, by Trump supporters seeking to overturn the election.

Earlier this month, a man from North Carolina was detained after parking his van near the Capitol in Washington and claiming to have a bomb while voicing anti-government grievances on a Facebook livestream.

Charged with threatening to use a weapon of mass destruction and attempting to use an explosive device, Floyd Ray Roseberry faces life in prison. He told a judge he had not taken his “mind medication”. A court-appointed psychologist found him to have bipolar disorder.

Some defendants in cases stemming from the 6 January attack have cited “Foxitis”, saying too much exposure to Fox News convinced them the election was stolen by Democrats.

Carlson is not the only prominent rightwinger to raise the idea of armed revolt.

On Sunday, the North Carolina Republican congressman Madison Cawthorn, a gadfly on the extreme right of the party, said at an event in his state that Joe Biden was not properly elected.

He also said widespread election fraud, which supporters of Donald Trump continue to claim without evidence, would “lead to one place, and that’s bloodshed”.

“And I will tell you,” Cawthorn said, “as much as I am willing to defend our liberty at all costs, there’s nothing that I would dread doing more than having to pick up arms against a fellow American. And the way that we can have recourse against that is if we all passionately demand that we have election security in all 50 states.”

A spokesman for Cawthorn told CNN the congressman was “clearly advocating for violence not to occur over election integrity questions” and “fears others would erroneously choose that route and strongly states that election integrity issues should be resolved peacefully and never through violence”.