Diane Abbott has had the Labour Party whip suspended after she suggested Jewish, Irish and Traveller people have never been “subject to racism”.
The former shadow home secretary later apologised “unreservedly” for any “anguish” and said she withdrew the comments.
But a Labour Party spokesperson said on Sunday: “The Labour party completely condemns these comments which are deeply offensive and wrong.
“The chief whip has suspended the Labour whip from Diane Abbott pending an investigation.”
It means the veteran MP will now sit in the Commons as an independent.
In a letter to The Observer, Abbott responded to an article by Tomiwa Owolade titled: “Racism in Britain is not a black and white issue. It’s far more complicated”.
Abbott said: “Owolade claims that Irish, Jewish and Traveller people all suffer from ‘racism’
“They undoubtedly experience prejudice. This is similar to racism and the two words are often used as if they are interchangeable.
“It is true that many types of white people with points of difference, such as redheads, can experience this prejudice.
“But they are not all their lives subject to racism. In pre-civil rights America, Irish people, Jewish people and Travellers were not required to sit at the back of the bus.
“In apartheid South Africa, these groups were allowed to vote. And at the height of slavery, there were no white-seeming people manacled on the slave ships.”
The comments were branded “appalling, offensive and ignorant” by Karen Pollock, the chief executive of Holocaust Educational Trust.
Grant Shapps, the energy secretary, said: “Once again, Jewish people have to wake up and see a Labour MP casually spouting hatful anti-Semitism.”
Jon Ashworth, Labour’s shadow work and pensions secretary, said Abbott’s comments “sounded utterly offensive”.
Jon Lansman, who founded the pro-Jeremy Corbyn campaign group Momentum, said: “A disgraceful comment by @HackneyAbbott for which she has rightly been suspended from the Labour Party. Racism is not a competition!”
Labour MP Margaret Hodge said Abbott’s letter “was deeply offensive and deeply depressing”.
“Keir Starmer’s response is right. No excuses. No delays,” she said.
In her apology, published after the outcry, Abbott said: “I wish to wholly and unreservedly withdraw my remarks and disassociate myself from them.
“The errors arose in an initial draft being sent. But there is no excuse, and I wish to apologise for any anguish caused.
“Racism takes many forms, and it is completely undeniable that Jewish people have suffered its monstrous effects, as have Irish people, Travellers and many others.
“Once again, I would likely to apologise publicly for the remarks and any distress caused as a result of them.”
Abbott has been the MP for Hackney North and Stoke Newington in London since 1987.
A close ally of Corbyn, she served as shadow home secretary during his time as Labour leader.
Corbyn has been formally blocked from standing as a Labour candidate at the next election after claiming anti-Semitism in the party while he was leader had been “overstated” by his political opponents.