The leader of Britain's Labour Party is calling anti-Semitism an evil that must be wiped out as he hits back against claims that he has allowed prejudice to spread in the left-of-center party.

Jeremy Corbyn told Labour's conference on Wednesday that anti-Semitism "led to the worst crimes of the 20th century. Every one of us has a responsibility to ensure that it is never allowed to fester in our society again."

Labour has been riven by conflict since veteran socialist Corbyn was elected leader in 2015. Some critics of the strongly pro-Palestinian politician say anti-Semitic abuse has gone unchecked during his tenure.

Corbyn acknowledged that "robust debate has at times spilled over into abuse and hate ... including misogyny and anti-Semitism, especially on social media." He called that "utterly unacceptable."