Britain's opposition Labour Party suspended former London mayor Ken Livingstone on Thursday in a row over anti-Semitism, as the party struggles with deep divisions since electing a hard-left leader last summer.
Most Labour lawmakers had demanded that leader Jeremy Corbyn suspend Livingstone.
The Labour party has been struggling to pull together after Corbyn swept into the leadership in September on a wave of enthusiasm, particularly among younger members, for change and an end to "establishment politics."
Corbyn's views have often jarred with many Labour lawmakers in parliament, however, dividing the party at a time when it is trying to hold the government, which is also deeply split over Britain's membership of the European Union, to account.
"Ken Livingstone has been suspended by the Labour Party, pending an investigation, for bringing the Party into disrepute," the Labour Party said in a statement.
Another lawmaker, John Mann, had been summoned over his behaviour after he was filmed shouting "You've lost it" at Livingstone
He also accused Livingstone of being a "Nazi apologist" after the former mayor said that Hitler had supported Zionism "before he went mad and ended up killing 6 million Jews."
Prime Minister David Cameron condemned the comments, saying anti-Semitism, like racism, was unacceptable.
"It is quite clear that the Labour Party has a problem with anti-Semitism," David Cameron said.
Jewish leaders said the party should introduce a zero-tolerance policy against anti-Semitism and some Labour lawmakers, including the party's candidate for mayor in an election next week, distanced themselves from Livingstone.
Mark Regev, Israel's ambassador to Britain, tweeted after Livingstone's suspension: "Not sure which is worse, deliberately distorting Hitler's goals or accusing his Jewish victims of being his partners."
The former mayor made his comments while mounting a defence of another lawmaker, Naz Shah, 42, who in 2014 had expressed views on Facebook supporting the relocation of Israel to the United States.
Shah was "administratively suspended" from the party on Wednesday pending investigation and has apologised for her remarks.
In an interview with BBC London, Livingstone said neither Shah nor the Labour Party were anti-Semitic.
"I've heard a lot of criticism of the state of Israel and its abuse of Palestinians, but I've never heard someone be anti-Semitic," Livingstone said.
"Let's remember when Hitler won his election in 1932, his policy then was that Jews should be moved to Israel. He was supporting Zionism - this before he went mad and ended up killing 6 million Jews."
Corbyn's leadership has been marred by rows over issues including national security and foreign policy that some lawmakers fear could keep the party out of power for more than a decade. Local elections next week could fuel discontent with Corbyn if Labour loses seats.