Tens of thousands of people attended a memorial service in Arizona for Charlie Kirk, the right-wing United States activist and founder of Turning Point USA, who was shot dead this month.

The event took place on Sunday at State Farm Stadium in Glendale, which seats more than 63,000 people. Organisers said additional space was arranged nearby to accommodate overflow crowds.

President Donald Trump, Vice President JD Vance and several other Republicans addressed the gathering, which Turning Point USA called “Building a Legacy: Remembering Charlie Kirk”.

Trump described Kirk as an “American martyr” in his address.

“He’s a martyr now for America’s freedom,” Trump said. “I know I speak for everyone here today when I say that none of us will ever forget Charlie. And neither now will history.”

Kirk’s widow, Erika, who recently became the organisation’s chief executive, also spoke, saying that she forgave Kirk’s killer.

In Glendale, Al Jazeera’s Phil Lavelle said that it was “impossible to say how many people are going to be here because this is not a ticketed event, people were just asked to register online”.

“But we spoke to one woman a few moments ago, who said she had no hope of getting in because of the number of people attending,” Lavelle added.

The Department of Homeland Security classified the service as an event of “the highest national significance”, a designation usually reserved for occasions such as the Super Bowl. Officials said that tight security measures were in place due to Trump’s attendance and the political tension surrounding Kirk’s killing.

“You thought you could kill Charlie Kirk? You have made him immortal,” said the White House’s deputy chief of staff, Stephen Miller. “You have no idea the dragon you have awakened. You have no idea how determined we will be to save this civilisation; to save the West; to save this republic.”

People began lining up before dawn to secure a spot inside the stadium, which is located west of Phoenix, where Kirk’s Turning Point organisation is based. The speakers, including US Secretary of State Marco Rubio and Secretary of Defense Peter Hegseth, delivered their tributes from behind bulletproof glass.

Billionaire Elon Musk, who has in recent years advocated for several far-right causes, was also in attendance, sitting next to Trump, months after leaving his role in the Department of Government Efficiency (DOGE).

“Charlie joined a long line of courageous men and women who were martyred for what they believe,” said Donald Trump Jr, the president’s son, who had a close relationship with Kirk.

“Charlie was my brother. Charlie was my commanding officer,” added Jack Posobiec, a right-wing influencer, in his tribute. “And we will never, ever let the left, the media or the Democrats forget the name of Charlie Kirk.”

Kirk, 31, was killed on September 10 during a university event in Utah. Police charged a 22-year-old suspect with murder, saying he carried out the attack alone and killed Kirk because he had had “enough of his [Kirk’s] hate”.

Kirk was a polarising figure, who called for the use of tear gas, rubber bullets and whips against immigrants at the US-Mexico border, suggested Islam was a danger to American society, and claimed there was “no factual data to back up global warming”.

The US right wing viewed Kirk as a major figure in the Trump movement, who played a pivotal role in building support for the US president and conservative causes among young people.

“Social media plays such an integral role in politics, and Charlie Kirk was seen as somebody who really managed to pull in the youth vote through this, managing to leverage and use TikTok to spread his message,” Lavelle, the Al Jazeera spoke with outside the service, said.

Jennifer Nicoll Victor, an associate professor of political science at George Mason University, told Al Jazeera that the memorial was marked by “a lot of rhetoric about Kirk himself, and a lot of Christian rhetoric”.

“It’s a little unusual to see so much Christian mythology combined with patriotism and nationalism.

“This is the intersection where Charlie Kirk fit within the Republican Party and the movement he was building,” she said, noting that “high-profile funerals historically can become lightning rods”.

“The political grief, and the conservative mobilisation around it, risk pushing us towards escalation rather than reconciliation,” Victor added.

Trump has been accused of exploiting Kirk’s murder for political gain by linking the killing to what he calls “left-wing extremism”, despite law enforcement dismissing claims of a wider alleged assassination plot. His remarks have drawn criticism from opponents who accused him of inflaming political divisions.

Kirk established Turning Point USA in 2012 at the age of 18. The organisation has grown into one of the largest right-wing groups in the US, with influence across high schools, universities and social media platforms.

A staunch supporter of Israel, Kirk’s death has also been mourned by Israeli leaders, including Prime Minister Benjamin Netanyahu, who described him as a “lion-hearted friend of Israel”, in a social media post shared on the day he was shot.