WASHINGTON — House Democrats plan to move on Wednesday to formally rebuke Representative Paul Gosar, Republican of Arizona, and strip him of committee assignments for posting an animated video depicting him killing a Democratic congresswoman and attacking President Biden.

Democratic leaders intend to hold a vote to censure Mr. Gosar — the most severe punishment in the House of Representatives short of expulsion — and oust him from his seats on the House Oversight and Natural Resources Committees. The action comes a week after he used his official social media accounts to circulate a video clip from a popular anime program altered to show a figure with Mr. Gosar’s face slashing the neck of another figure bearing the face of Representative Alexandria Ocasio-Cortez, Democrat of New York.

It also showed his character swinging swords at Mr. Biden.

“That is an insult — not only an endangerment of that member of Congress — but an insult to the institution” of the House, Speaker Nancy Pelosi of California told reporters on Tuesday. “We cannot have members joking about murdering each other, as well as threatening the president of the United States.”

Mr. Gosar has not apologized and instead played down the video, claiming in a statement that it was “truly a symbolic portrayal of a fight over immigration policy” and saying he would not “espouse violence or harm toward any member of Congress.” He has privately blamed aides for posting the video.

“It is a symbolic cartoon,” Mr. Gosar said in a statement. “It is not real life.”

In a separate interview with conservative media, Mr. Gosar said he and his office were “trying to reach out to the younger generation that likes these anime.”

House Republican leaders have not publicly condemned Mr. Gosar for the video, which surfaced as prominent members of the party have become increasingly tolerant of violent statements, and their core supporters have resorted to threats against lawmakers considered insufficiently loyal to the G.O.P. line.

In the resolution scheduled for action on Wednesday, Democrats refer to Republicans’ inaction and draw a connection between Mr. Gosar’s video and the Capitol riot, stating that “depictions of violence can foment actual violence and jeopardize the safety of elected officials, as witnessed in this chamber on Jan. 6, 2021.”

Mr. Gosar’s post is the latest in a series of controversies involving the sixth-term congressman, who occupies a bizarre corner of far-right internet culture. Mr. Gosar has emerged as the most prominent congressional ally of an alt-right white nationalist group called America First whose followers embrace the use of off-kilter, frequently ironic memes. For years, he has elevated a slew of conspiracy theories and falsehoods — including that the 2020 presidential election was stolen — and cultivated a hard-right online base as a result.

He raised eyebrows in March after tweeting a meme featuring a man asking a prostitute to “tell everyone America First is inevitable,” the tagline of the white nationalist group.

For Democrats, the animated video was the final straw.

“This was a vile, dangerous incitement to violence,” said Representative Steny H. Hoyer of Maryland, the majority leader. “I have not seen something so egregious in my 40 years of service in the Congress of the United States, and unfortunately it’s a pattern.” He said he wished Republican leaders would act to discipline Mr. Gosar on their own, but added, “action must be taken.”

In the resolution, Democrats took Mr. Gosar to task for targeting Ms. Ocasio-Cortez, asserting that “violence against women in politics is a global phenomenon meant to silence women and discourage them from seeking positions of authority and participating in public life, with women of color disproportionately impacted.”

Republicans have said the Democratic majority has been setting a dangerous precedent by acting against individuals in the minority. Earlier this year, the Democratic-led House voted to strip Representative Marjorie Taylor Greene, Republican of Georgia, of her committee assignments after social media posts emerged from before her election in which she endorsed violence against Democrats in Congress.

“In future years, this precedent may be used to give the majority veto power over the minority’s committee assignments,” said Representative Tom Cole, Republican of Oklahoma. “That’s a dangerous, dark road for the institution to go down.”

Representative Kevin McCarthy of California, the Republican leader, has declined to publicly denounce the video, but told reporters on Tuesday that he has told lawmakers that he would not accept “any action or showing of a violence to another member.” Mr. McCarthy said he had called Mr. Gosar after the Arizona Republican posted the video, and noted that he had deleted the video after their call.

The last time the House censured a lawmaker was in 2010, after a yearslong ethics investigation found Representative Charles B. Rangel, Democrat of New York, guilty of a litany of abuses including failing to pay his income taxes and misuse of his office to solicit campaign donations.

Jonathan Weisman contributed reporting.