(CNN) An anti-Muslim poster associating US Rep. Ilhan Omar with the September 11 attacks appeared Friday at a Republican-sponsored public gathering at the West Virginia statehouse, creating a firestorm of controversy that apparently led one official to resign.

The poster, featuring pictures of Omar and the terror attacks in a fashion of an Internet meme, was displayed behind a table during WVGOP Day at the Capitol , an event in which the West Virginia Republican Party had invited the public to the Capitol's upper rotunda.

The state GOP denounced the sign, saying that an exhibitor had put it up without its knowledge and that it demanded its removal.

Omar, a Minnesota Democrat who became one of the first two Muslim women to be elected to Congress last year, branded it as "the GOP's anti-Muslim display."

"No wonder why I am on the 'Hitlist' of a domestic terrorist and 'Assassinate Ilhan Omar' is written on my local gas stations," the Somali-American posted to Twitter on Friday. "Look no further, the GOP's anti-Muslim display likening me to a terrorist rocks in state capitols and no one is condemning them!"

No wonder why I am on the "Hitlist" of a domestic terrorist and "Assassinate Ilhan Omar" is written on my local gas stations.



Look no further, the GOP's anti-Muslim display likening me to a terrorist rocks in state capitols and no one is condemning them! https://t.co/0ouCaloWqh — Ilhan Omar (@IlhanMN) March 1, 2019

Her mention of a hit list refers to recent news in which a US Coast Guard officer was accused of writing a hit list of prominent Democrats and journalists . Court documents say the congresswoman was named on that list.

under criticism from members of both parties for suggesting that pro-Israel groups effectively buy off politicians and push allegiance to a foreign country. Friday's incidents came as Omar has come

Poster leads to fierce arguments

The poster created tumult at the Capitol in Charleston, some 750 miles away from Omar's Minneapolis-area congressional district.

With images and text, the display suggested that Omar's election is proof that Americans have forgotten the September 11 attacks.

The poster's top picture was of the World Trade Center's twin towers engulfed in smoke and flames, topped with the words, " 'Never forget' -- you said."

The bottom picture was of Omar, accompanied by the words, "I am the proof -- you have forgotten."

Arguments ensued in the rotunda over the poster, involving even lawmakers who were in the building for a House session, WCHS reported.

A state lawmaker has alleged that during these arguments, a different woman -- Anne Lieberman, the House sergeant-at-arms -- countered criticisms of the sign by equating all Muslims with terrorists.

Lieberman eventually resigned Friday. Her short resignation letter, read by a House clerk while the chamber was in session, did not mention her reasons for the resignation or the allegation against her.

Lieberman, according to West Virginia Public Broadcasting , disputed that she called all Muslims terrorists. CNN's attempt to reach Lieberman wasn't immediately successful.

The lawmaker who accused Lieberman of making the comment, Delegate Michael Angelucci, D-Marion, railed against the alleged remarks on the chamber's floor.

"That's beyond shameful, and that's not freedom of speech," Angelucci said, referring to the alleged comment, according to WCHS. "That's hate speech, and it has no place in this House -- the people's House."

Democratic Delegates Michael Angelucci, left, and Mike Caputo denounced the poster Friday in the West Virginia House.

Report: Person injured when a lawmaker kicked open a door

The emotional arguments over the poster may have led to at least one injury. Delegate Mike Caputo, D-Marion, admitted on the House floor to having kicked open a door out of anger over the display.

House officials said the door hit a doorman, who sustained an unspecified injury, according to WCHS.

"Yeah, I kicked that door open. I'll own it," Caputo said on the House floor later Friday. "And I said some things that I don't normally say. So the point should be, we shouldn't do what's going on outside here, whether it's the Democratic Party or the Republican Party. (There's) no place for that."

House speaker says incidents are under investigation

Speaker Roger Hanshaw, R-Clay, said leaders are investigating the incidents.

"The West Virginia House of Delegates unequivocally rejects hate in all of its forms. As we began today's floor session, we had a series of incidents occur in and outside of our Chamber that absolutely do not reflect the character and civility the people of this state demand of their public servants," Hanshaw said in a statement Friday.

"Leadership of the House of Delegates is currently working to investigate these incidents to learn firsthand the factual basis of what occurred, and will respond with appropriate action."

State GOP distances itself from the poster

The West Virginia Republican Party released a statement Saturday saying it "does not approve, condone, or support hate speech."

"One of the exhibitors at our West Virginia Republican Party Day at the Capitol displayed a sign that we did not approve, were not aware of before the day started, and we do not support," the statement said. "Upon learning about the sign, we immediately asked this exhibitor to remove the sign.

"Our party supports freedom of speech, but we do not endorse speech that advances intolerant and hateful views. We have shown that when West Virginians are united, when we respect each other, embrace our differences and focus on moving our state forward what we can accomplish."

During Friday's House session, some state lawmakers debated whether the sign was a display of free speech. Hanshaw told the group that, regardless of whether it was or wasn't, the resulting chaos was unbecoming and unlike the typical behavior of the Legislature.

"For the last 52 days, we have allowed national-level politics to become a cancer on our state," Hanshaw said in his address.

"To the ladies and gentlemen who are watching these cameras, we owe it to you to do better. We are supposed to be the model of democracy."