The British Labour leader said the MP "was taken from us in an act of hatred"
David Cameron and Jeremy Corbyn have come together in a show of unity to pay their respects to Labour MP Jo Cox.
The British prime minister and Labour leader were joined by House of Commons Speaker John Bercow for a visit to the politician's constituency, a day after the mother of two was killed in a street attack.
With campaigning in the EU referendum suspended, it has also been announced that the UK parliament will be recalled on Monday, so MPs can pay tribute to the 41-year-old.
Standing alongside the Conservative leader, Mr Corbyn said: "Jo was brutally murdered here 24 hours ago in this town - a town she loved, a town she grew up in, serving a community she loved.
"She was taken from us in an act of hatred, in a vile act that has killed her. It's an attack on democracy, what happened yesterday.
"It's the well of hatred that killed her."
Mr Cameron said the nation was "rightly shocked" at her death, adding: "Two children have lost their mother, a husband has lost a loving wife and Parliament has lost one of its most passionate and brilliant campaigners."
He added: "If we truly want to honour Jo, then what we should do is recognise that her values - service, community, tolerance - the values she lived by and worked by, those are the values that we need to redouble in our national life in the months and years to come."
The united front came as Downing Street announced the Conservative party would not contest the by-election in Batley and Spen resulting from Mrs Cox's death.
The Liberal Democrats and UKIP have also agreed not to put up anyone in the constituency.
The MP died after being shot and stabbed outside her constituency advice surgery in Birstall on Thursday.
Her assailant reportedly shouted "Britain first" during the deadly assault.
Ghulam Maniyar said his daughter, Fazila Aswat, had tried to help the politician as she lay dying in her arms.
Following her killing, politicians have been advised to review their security.
The alleged gunman has been named as Tommy Mair, 52, who was described by neighbours as a "loner" who "kept himself to himself".
He was arrested close to the scene of the attack a short time later. Police have also searched his house.
However, his brother has said he was "not a violent man".
Following the MP's death, her husband Brendan released a statement in which he said: "Jo believed in a better world and she fought for it every day of her life with an energy and a zest for life that would exhaust most people."
It has also emerged that three months ago a man was cautioned for sending the MP "malicious communications".
However police have confirmed it was not the same man who was arrested on Thursday following the attack.