"She equates the United States and Israel with the worst terrorists in the world. She's a menace," Fleischer said on "Outnumbered." "She's a reckless congresswoman whose judgment is awful."
Omar is under fire from even some Democratic colleagues after comparing the United States and Israel to the terrorist organizations Hamas and the Taliban. The "Squad" member was forced to offer a "clarification" and say she was not suggesting all were on an equal field of committing war crimes. Speaker Nancy Pelosi, D-Calif., was eager to move on and thanked Omar for her remarks, telling CNN on Sunday "end of subject."
"Except it's not the end of the subject. The subject continues, because Ilhan Omar continues to say these things," Fleischer said. "The fundamental problem is you really have a member of Congress whose ideas are the antithesis of democracies defending themselves."
Omar has previously drawn criticism for tweeting Israel had "hypnotized" the world and suggesting that a pro-Israel organization paid politicians to support the Jewish state, in addition to her support for the anti-Israel Boycott, Divestment, and Sanctions (BDS) movement. Last week, she also retweeted a video from the anti-Israel International Solidarity Movement, which was previously investigated by the FBI for possible terrorist ties.
She also raised eyebrows when she once referred to the 9/11 terrorist attacks with the flippant comment, "Some people did something."
Fleischer said she hoped she would lose her committee assignments, which was the same fate of right-wing firebrand Rep. Marjorie Taylor Greene, R-Ga., over her past embrace of QAnon and other conspiracy theories.
Fellow "Squad" member Rep. Rashida Tlaib, D-Mich., was outraged after Pelosi and other Democratic leaders called out Omar for her remarks equating the U.S. and Israel with terror groups, claiming, "Freedom of speech doesn't exist for Muslim women in Congress."
On the flipside, Fox News host Kayleigh McEnany said today's Democratic Party found anti-Semitic rhetoric to be "acceptable" with most of its members falling silent on Omar's language.
"You have 12 Democrats, only 12 Democrats in Congress, who signed on to a rebuke of Ilhan Omar," she said. "Where are the other Democrats … Their silence is deafening."
Fox News' Houston Keene contributed to this report.