Three years after a gunman killed 49 people in Orlando, Florida’s, Pulse nightclub, 2020 Democratic presidential candidate Pete Buttigieg remembered the nation’s deadliest attack on the LGBTQ community.

“Pulse wasn’t an attack on just one community ― it was an attack on LGBTQ Americans, Latinx Americans, and Black Americans,” the South Bend, Indiana, mayor, who is openly gay, said in an email to supporters on Wednesday. “It was an attack on people who look like me, and an attack on people who look nothing like me. It was an attack on all of us. It was an attack on individuals expressing their sexuality, their heritage, their gender, and their freedom.”

The 2016 massacre unfolded on the venue’s Latin-themed night just before closing time when Omar Mateen, a U.S. citizen who claimed to be an ISIS soldier, stormed the building with an assault-style rifle and semiautomatic pistol. In addition to the dead, more than 50 people were injured and dozens were held hostage during a three-hour standoff that ended with the shooter’s death in an early morning police shootout.

At the time, it was the worst mass shooting by a single shooter in U.S. history. It was surpassed by the massacre of 58 people at a Las Vegas country music festival in 2017.

For Buttigieg, Wednesday wasn’t only a time to pay tribute to the victims. It was a time to call for gun control and anti-hate crime legislation.

“Change will not just happen,” he said. “It will only come as the result of struggle – political struggle, moral struggle. We need Congress to deliver on common-sense gun safety laws supported by an American majority, like universal background checks and a ban on military-style assault weapons. And we need to incentivize every state to pass a hate crimes law.”

Other 2020 Democratic hopefuls offered messages of their own, including former Rep. Beto O’Rourke (Texas) and Sens. Elizabeth Warren (Mass.), Kamala Harris (Calif.) and Cory Booker (N.J.), who vowed to “end the NRA’s reign & pass gun safety policy to save lives.”

“We can ― and we will ― build a nation based on love & respect for one another,” Booker added in a tweet.

Florida lawmakers on Monday introduced a bill to designate Pulse as a national memorial.