The Labour Party "will not be divided" in the battle to combat racial discrimination in all its guises, Jeremy Corbyn has said.
In a video message, the Labour leader blamed an apparent spike in episodes of racial abuse since the Brexit vote on the Government's "apathetic" approach to human rights issues.
He added that his party - which became embroiled in a row over its handling of anti-semitism allegations last year - must "come together to celebrate our diverse communities".
In the clip, released to commemorate UN International Day for the Elimination of Racial Discrimination on Tuesday, he said: "There could not be a more important time to redouble our efforts in fighting racism Islamophobia, anti-semitism and all forms of discrimination.
He added: "Labour will continue to fight against prejudice and fight for the communities we represent.
"We will not be divided, in place of division we must all come together to celebrate our diverse communities and our shared heritage."
His call for unity comes as infighting continues to rage among high-profile Labour figures amid accusations the party is facing a hard-left takeover aided by a union chief.
On Tuesday, Unite union general secretary Len McCluskey accused the party's deputy leader Tom Watson - who issued the warning - of living in a "world of skulduggery, smears and secret plots".
Mr Corbyn also used his video address to point to a recent survey from the Trades Union Congress - which it claimed showed the Brexit vote gave "racism a new lease of life" - as evidence of government failings.
Referring to the Government's refusal to guarantee the rights of EU residents in the UK ahead of forthcoming negotiations, he said: "The Tories are treating people in Britain as bargaining chips instead of human beings.
"When the Government is so apathetic towards human rights it's no surprise that a report just published by the Trades Union Congress has found that one in three black, Asian and minority ethnic people have experienced or witnessed racist abuse since the Brexit vote."