The poster, which was displayed on a table in the rotunda in the Capitol, showed a split picture of the World Trade Center on fire on top of a snap of Omar.
“’Never Forget’ – You said..” the caption on the picture of the twin towers read.
Meanwhile, the caption of the picture of Omar read, “I am the proof you have forgotten.”
The poster was part of the display for “WV GOP Day,” which is when the “Republicans Take the Rotunda,” NBC News reported.
Omar became the first Somali-American elected to Congress in November. She is one of the first two Muslim women elected to Congress, along with Democrat Rashida Tlaib.
It was not immediately clear who put up the poster, but lawmakers got into a heated dispute over the display. The argument even became physical, leaving a doorkeeper allegedly injured and a lawmaker resigning.
A few Democratic lawmakers condemned the poster and allegedly got into a feud with Anne Lieberman, the House’s sergeant-at-arms, “after she allegedly made an anti-Muslim remark,” NBC News reported. Lieberman denied the remark but resigned Friday following the allegation.
Democratic lawmaker Mike Caputo allegedly injured a doorkeeper during a heated argument, WSAZ reported.
The House has 59 Republicans and 41 Democrats. House Speaker Roger Hanshaw said the incident was being investigated.
"We have allowed national-level politics to become a cancer on our state ... to invade our chamber in a way that makes me ashamed,” he said in remarks on the floor. “We can do better.”
Democrat Mike Pushkin called the poster “racist” and “wrong.” He said no Republicans condemned the display.
“I’m really disappointed that not a single Republican elected official in this building could join me in saying it’s wrong,” he told The Washington Post.
Omar responded to the poster in a tweet on Friday.
“No wonder why I am on the ‘Hitlist’ of a domestic terrorist and ‘assassinate Ilhan Omar’ is written on my local gas stations,” she wrote. “Look no further, the GOP’s anti-Muslim display likening me to a terrorist rocks in state capitols and no one is condemning them!”
The Associated Press contributed to this report.