Hundreds of people have attended a vigil for Charlie Kirk in central London, with speakers hailing him as a "Christian martyr" and calling for people to wage a "war on evil".
Father-of-two Mr Kirk, 31, a Donald Trump ally and co-founder and chief executive of the youth right-wing organisation Turning Point USA, was shot and killed at a Utah Valley University show on Wednesday, in what authorities called a political assassination.
After the shooting, US President Mr Trump called Mr Kirk a "martyr for truth and freedom" and blamed the rhetoric of the "radical left" for the killing.
Hundreds of people attended the vigil organised by activists from Turning Point UK on Friday evening by the statue of Field Marshal Montgomery in Whitehall - with many waving Union flags and a number of others wearing "Make England Great Again" (MEGA) hats.
A large portrait of Mr Kirk was held up high up by the statue as Turning Point UK chief executive Jack Ross addressed the crowd calling for left-wingers to "be careful with their rhetoric".
"We will not be intimidated, we will not be bullied out of standing up for our country, our values, and our people," Mr Ross said.
"Despite what certain members of the press have purported, Charlie was not a hateful far-right bigot: he was a good Christian man and his desire to help people came from his passion for Christ."
He added: "I take this opportunity to ask people, especially those of the left wing of politics, that they must be careful with their rhetoric.
"Whilst sticks and stones do break bones, it is words that encourage people to pick up those sticks."
Mr Kirk co-founded Turning Point USA aged 18 to take his brand of Christian conservatism, advocating for low taxes and limited government, on to college campuses.
He attracted a big online following, often posting videos of his confrontations with liberal students who questioned him on issues including abortion, gun rights and transgender rights, with his views drawing fierce criticism from some.
Nick Tenconi, COO of Turning Point UK and leader of the UK Independence Party, told the crowd the shooting of Mr Kirk marked the beginning of a "war on evil" and called for people to carry on Mr Kirk's legacy.
"I say, ladies and gentlemen, Charlie Kirk is a hero," he said.
"When they try to cancel us, when they try to silence us, when they murder us, they create martyrs, and Charlie is a Christian martyr."
He went on: "We are at war with evil, we must end the madness, we must destroy evil: I say we are commanded as Christians not to make peace with evil, but to destroy it.
"We are under attack, each and every one of us, and we must defend ourselves. War has now been declared."
The crowd responded to his speech by singing "Christ is king".
Married father-of-two Beau Thomas, 34, from Haywards Heath in West Sussex, put down a bouquet of flowers by the large Union flag that was hung to the fence near the Montgomery statue.
He said: "He (Charlie Kirk) was someone that we looked up to as a family, someone that we found inspirational, someone that stood up for many of same things we believe in.
"I'm Christian myself and Charlie shared his Christian beliefs, and he did it articulately, he did it with love, he did it with virtue and good character; so what happened to him is just an awful tragedy.
"He was a family man; he was a husband; he's already contributed so much to this world and the things he believed in—and he did that peacefully; he did it with compassion and love for others.
"Charlie stood up for what he believed in—and people that disagree with that may call that divisive; they may call it hateful—but it doesn't mean that it is.
"People are free to share what they believe as long as they do it peacefully—and Charlie always did that."
A man and a woman who preferred to remain anonymous, both 26 and from London, came to the vigil holding a picture of Mr Kirk with the words "In Memoriam".
The man said: "The scenes that I saw in Utah were really shocking, and regardless of your opinions of Charlie Kirk I think that no one should have to die for their political beliefs."
Asked how he would respond to people who argue Mr Kirk's views were divisive and harmful, he replied: "I think words are words, and violence is violence.
"I don't think words can be violent.
"You can incite violence, but I've never seen Charlie Kirk do that.
"I've always seen him engage in debate in good will and try to have an honest polite conversation with people."
The motive for the shooting remains unclear, but Utah governor Spencer Cox announced in a US press conference on Friday a man called Tyler Robinson had been arrested, adding: "We got him."
Robinson, 22, had become "more political" in the run-up to the shooting and had indicated to a family friend afterwards that he was responsible, Mr Cox said.