Republicans have ousted Democrat Ilhan Omar from her committee post in a sign of escalating tensions in the US Congress.
They voted to remove Ms Omar from the House Foreign Affairs Committee over her past comments about Israel.
Republicans said the move sent a strong statement against antisemitism.
But Democrats and Ms Omar said it was revenge after two Republicans were ousted from committees in 2020 when Democrats held a House majority.
Ms Omar also suggested she was being removed because she is a Muslim woman who immigrated to the US as a refugee.
Is anyone surprised that I am somehow deemed unworthy to speak about American foreign policy?” she said shortly before the vote.
Republicans secured a majority in the House of Representatives following the midterm elections in November, and members voted along party lines to remove Ms Omar on Thursday.
She is one of three high-profile Democrats to lose a committee assignment under the new House majority, which is led by Speaker Kevin McCarthy.
Some Republicans – including Mr McCarthy – argued Ms Omar should not serve on the powerful Foreign Affairs Committee owing to her past comments about Israel that have, at times, been criticised by members from both parties.
Ms Omar apologised in 2019 for implying money was behind support for Israel.
Then-Democratic leader Nancy Pelosi condemned Ms Omar’s comments as antisemitic as they invoked bigoted stereotypes about Jewish people using money for influence.
“Antisemitism is real and I am grateful for Jewish allies and colleagues who are educating me on the painful history of antisemitic tropes,” Ms Omar said in a statement at the time.
On Thursday, Democrats, including Jewish members of Congress, said Ms Omar had taken appropriate steps to educate herself about antisemitism.
Historically, the party in power in the House rarely disciplines members of the opposition themselves, but that has begun to change, creating a new form of partisan gamesmanship that could further divide the chamber.
In 2020, Democrats removed Marjorie Taylor Greene and Paul Gosar from their committees, citing comments and social media posts directed at Democrats, including Ms Omar.
Mr McCarthy later on Thursday denied the decision to remove Ms Omar from the Foreign Affairs Committee was a “tit-for-tat” after Ms Greene and Mr Gosar’s removal.
“We’re not removing her from other committees,” he told reporters. “We just do not believe when it comes to foreign affairs, especially with the responsibility of that position around the world, with the comments that you make, she shouldn’t serve there.”
Congressman Max Miller, an Ohio Republican who introduced the resolution to formally remove Ms Omar from the committee, said her “discriminatory” comments towards Israel and tense relationship with a foreign ally disqualified her.
But Democratic congresswoman Kathrine Clark said ousting Ms Omar would deprive the committee of “a refugee and a survivor of war” who “knows first-hand what is at stake in its work”.
Other members said the decision risked escalating partisan rancour in the House.
Ms Omar, who represents parts of Minnesota, arrived in the United States in the 1990s as a Somali refugee. In 2018, she became one of the first Muslim women elected to the US Congress.
She has received well-publicised abuse during her time in office – and supporters of former President Donald Trump have previously chanted “send her back!” at his rallies.
Before the vote on Thursday, Ms Omar said another death threat had been sent to her office. “These threats increase whenever Republicans put a target on my back,” she said.