The White House on Tuesday condemned the Republican congressman Paul Gosar for tweeting a video which depicted him striking the New York Democrat Alexandria Ocasio-Cortez with a sword and appearing to threaten Joe Biden.

“There is no place for any type of violence or that type of language in the political system,” the principal deputy White House press secretary, Karine Jean-Pierre, told reporters at a daily briefing. “It should not be happening, and we should be condemning it.”

The House speaker, Nancy Pelosi, said “threats of violence against members of Congress and the president of the United States must not be tolerated” and called on the House Republican leader, Kevin McCarthy, to “join in condemning this horrific video and call on the ethics committee and law enforcement to investigate”.

Twitter attached a hateful conduct warning to Gosar’s tweet, which was also posted to Instagram on Sunday, but kept it up online.

“This tweet violated the Twitter rules about hateful conduct,” Twitter’s message said. “However, Twitter has determined that it may be in the public’s interest for the tweet to remain accessible.”

The roughly 90-second video presents an altered version of a Japanese anime series, interspersed with shots of border patrol officers and migrants at the US border with Mexico.

In one section, characters whose faces are replaced with those of Gosar and fellow extremist Republicans Marjorie Taylor Greene of Georgia and Lauren Boebert of Colorado are seen fighting other characters.

Gosar’s character strikes another, made to look like Ocasio-Cortez, in the neck with a sword. The video ends with an apparent threat to Biden.

Ocasio-Cortez was in Glasgow on Tuesday, attending the Cop26 climate summit.

On Twitter, she wrote: “A creepy member I work with who fundraises for neo-Nazi groups shared a fantasy video of him killing me and he’ll face no consequences because [McCarthy] cheers him on with excuses … well, back to work because institutions don’t protect women of color.”

Ocasio-Cortez listed other instances of threatening behavior from Republicans in Congress.

“Remember when [Ted] Yoho accosted me on the Capitol [steps] and called me a f[uck]ing b[itch]. Remember when Greene ran after me a few months ago screaming and reaching. Remember when she stalked my office the first time with insurrectionists and people locked inside. All at my job and nothing ever happens. Anyways, back to business.”

The congresswoman also called Gosar “just a collection of wet toothpicks anyway”.

“White supremacy,” she said, “is for extremely fragile people and sad men like him, whose self concept relies on the myth that he was born superior because deep down he knows he couldn’t open a pickle jar or read a whole book by himself.”

Gosar is an ardent Trump ally who in 2018 was the subject of a campaign ad made by six of his siblings, exhorting voters to ditch him.

He is also among lawmakers whose phone or computer records are sought by the House committee investigating the deadly attack on Congress on 6 January, in which Trump supporters sought to overturn the former president’s election defeat.

On Monday, Eric Swalwell, a House California Democrat, said: “These bloodthirsty losers are more comfortable with violence than voting. Keep exposing them.”

The Yale historian Joanne Freeman, author of The Field of Blood, a well-regarded history of violence in Congress before the civil war, wrote: “Threats of violence lead to actual violence. They clear the ground. They cow opposition. They plant the idea. They normalize it. They encourage it. They maim democracy. And run the risk of killing it.”

The Associated Press contributed to this report