Labour has suspended Naz Shah from the party over comments she made criticising Israel in 2014 before she became an MP.
The mainstream media has targeted the Bradford West MP over Facebook posts she made before entering parliament, including one suggesting Israel should be moved to America.
She offered a “profound apology” in a statement to MPs for the posts which were made before she became an MP.
Addressing the Speaker, she said: “I hope you will allow me to say that I fully acknowledge that I have made a mistake and I wholeheartedly apologise to this House for the words I used before I became a member.
“I accept and understand that the words I used caused upset and hurt to the Jewish community and I deeply regret that. Anti-semitism is racism, full stop. As an MP I will do everything in my power to build relations between Muslims, Jews and people of different faiths and none.
“I am grateful and thankful for the support and advice I have received from many Jewish friends and colleagues, advice I intend to act upon. I truly regret what I did and I hope, I sincerely hope, that this House will accept my profound apology.”
Earlier party leader Jeremy Corbyn warned her about the “offensive and unacceptable” posts and David Cameron called for her suspension.
Labour said: “Jeremy Corbyn and Naz Shah have mutually agreed that she is administratively suspended from the Labour Party by the general secretary. Pending investigation, she is unable to take part in any party activity and the whip is removed.”
Shah had quit her job as as an unpaid aide to shadow chancellor John McDonnell over the remarks. Mr McDonnell said she had “done the right thing” in quitting and there was “now a formal process for the party to consider the matter”.
Mr Corbyn, who is under pressure to deal with allegations of anti-Semitism in the Labour Party, issued a statement about Ms Shah minutes before Prime Minister’s Questions.
He said: “What Naz Shah did was offensive and unacceptable. I have spoken to her and made this clear. These are historic social media posts made before she was a member of parliament. Naz has issued a fulsome apology. She does not hold these views and accepts she was completely wrong to have made these posts. The Labour Party is implacably opposed to anti-Semitism and all forms of racism.”
But Mr Cameron stepped up the pressure on the Labour leader at Prime Minister’s Questions, saying: “Anti-Semitism is effectively racism and we should call it out and fight it wherever we see it. And the fact that, frankly, we have a Labour Member of Parliament, with the Labour whip, who made remarks about the transportation of Israel to America, and talked about a ‘solution,’ and is still in receipt of the Labour whip is quite extraordinary.”
In a Facebook post in 2014, Ms Shah shared a graphic showing an image of Israel’s outline superimposed on a map of the US under the headline “Solution for Israel-Palestine conflict – relocate Israel into United States”, with the comment “problem solved.”
The post suggested the US has “plenty of land” to accommodate Israel as a 51st state, allowing Palestinians to “get their life and their land back.”
It added Israeli people would be welcome and safe in the US, while the “transportation cost” would be less than three years’ worth of Washington’s support for Israeli defence spending.
Ms Shah added a note suggesting the plan might “save them some pocket money”.
The post was brought to light by the right-wing Guido Fawkes website, which also highlighted a post in which she appeared to liken Israeli policies to those of Hitler.
In a statement, the MP said: “I made these posts at the height of the Gaza conflict in 2014, when emotions were running high around the Middle East conflict. But that is no excuse for the offence I have given, for which I unreservedly apologise.”
She set out a more detailed apology in an article for Jewish News.
“The language I used was wrong,” she wrote.
“It is hurtful. What’s important is the impact these posts have had on other people. I understand that referring to Israel and Hitler as I did is deeply offensive to Jewish people for which I apologise.”
The Board of Deputies of British Jews said the comments were “simply appalling”, calling for an urgent meeting “for clarification of her views on Israel and the UK Jewish community.”