WASHINGTON (AP) — Donald Trump was booed repeatedly while addressing the Libertarian Party National Convention on Saturday night, with many in the crowd shouting insults and decrying him for things like his COVID-19 policies, running up towering federal deficits and lying about his political record.

When he took the stage, many jeered while some supporters clad in “Make America Great” hats and T-shirts cheered and chanted “USA! USA!” It was a rare moment of Trump coming face-to-face with open detractors, which is highly unusual for someone accustomed to staging rallies in front of ever-adoring crowds.

Libertarians, who prioritize small government and individual freedoms, are often skeptical of the former president, and his invitation to address the convention has divided the party. Trump tried to make light of that by referring to the four criminal indictments against him and joking, “If I wasn’t a Libertarian before, I sure as hell am a Libertarian now.”

Trump tried to praise “fierce champions of freedom in this room” and called President Joe Biden a “tyrant” and the “worst president in the history of the United States,” prompting some in the audience to scream back: “That’s you.”

As the insults continued, Trump eventually hit back, saying “you don’t want to win” and suggesting that some Libertarians want to “keep getting your 3% every four years.”

Libertarian candidate Gary Johnson won about 3% of the national vote in 2016, but nominee Jo Jorgensen got only a bit more than 1% during 2020’s close contest.

Libertarians will pick their White House nominee during their convention, which wraps on Sunday. Trump’s appearance also gave him a chance to court voters who might otherwise support independent presidential candidate Robert F. Kennedy, Jr. who gave his own Libertarian convention speech on Friday.

Polls have shown for months that most voters do not want a 2020 rematch between Trump and President Joe Biden. That dynamic could potentially boost support for an alternative like the Libertarian nominee or Kennedy, whose candidacy has allies of Biden and Trump concerned that he could be a spoiler.

Despite the raucous atmosphere, Trump continued to press on with his speech, saying he’d come “to extend a hand of friendship” in common opposition to Biden. That prompted a chant of “We want Trump!” from supporters, but more cries of “End the Fed!” — a common refrain from Libertarians who oppose the Federal Reserve. One person who held up a sign reading “No wannabe dictators!” was dragged away by security.

Trump tried to win over the crowd by pledging to include a Libertarian in his Cabinet, but many in the crowd hissed in disbelief. The former president did get a big cheer when he promised to commute the life sentence of the convicted founder of the drug-selling website Silk Road, Ross Ulbricht, and potentially release him on time served.

That was designed to energize Libertarian activists who believe government investigators overreached in building their case against Silk Road, and who generally oppose criminal drug policies more broadly. Ulbricht’s case was much-discussed during the Libertarian convention, and many of the hundreds in the crowd for Trump’s speech hoisted “Free Ross” signs and chanted the phrase as he spoke.

Despite those promises, many in the crowd remained antagonistic. One of the candidates vying for the Libertarian presidential nomination, Michael Rectenwald, declared from the stage before the former president arrived that “none of us are great fans of Donald Trump.” After his speech, Rectenwald and other Libertarian White House hopefuls took the stage to scoff at Trump and his speech.

Those for and against Trump even clashed over seating arrangements. About two hours before the former president’s arrival, Libertarian organizers asked Trump supporters in the crowd to vacate the first four rows. They wanted convention delegates — many of whom said they’d traveled from around the country and bought expensive tickets to the proceedings — could sit close enough to hear the speech.

Many of the original seat occupants moved, but organizers eventually brought in more seats to calm things down.

The Libertarian split over Trump was reflected by Peter Goettler, president and chief executive of the libertarian Cato Institute, who suggested in a Washington Post column that the former president’s appearance violated the gathering’s core values and that “the political party pretending to be libertarian has transitioned to a different identity.”

Trump’s campaign noted that Biden didn’t attend the Libertarian convention himself, and argued that the former president’s doing so was part of an ongoing effort to reach would-be supporters in places that are not heavily Republican — including the former president’s rally Thursday in the Bronx during a pause in his New York hush money trial.

The Libertarian ticket will try to draw support from disaffected Republicans as well as people on the left. Such voters could also gravitate toward Kennedy.

Trump didn’t dwell on Kennedy on Saturday night. But, after previously praising him and once considering him for a commission on vaccination safety, the former president has gone on the attack against Kennedy. He suggested on social media that a vote for Kennedy would be a “wasted protest vote” and that he would “even take Biden over Junior.”

The former president, while in office, referred to the COVID-19 vaccine as “one of the greatest miracles in the history of modern-day medicine.” He’s since accused Kennedy of being a “fake” opponent of vaccines.

In his speech at the Libertarian convention, Kennedy accused Trump and Biden of trampling on personal liberties in response to the pandemic. Trump bowed to pressure from public health officials and shut down businesses, Kennedy said, while Biden was wrong to mandate vaccines for millions of workers.

For his part, Biden has promoted winning the endorsement of many high-profile members of the Kennedy family, in an attempt to marginalize their relative’s candidacy.

Kevin Munoz, a spokesperson for Biden’s reelection campaign, slammed Trump and top Republicans for opposing access to abortion and supporting limits on civil society, saying in a statement Saturday, that “freedom isn’t free in Trump’s Republican Party and this weekend will be just one more reminder of that.”