American gold medalist kneels during national anthem at the Pan Am Games

American gold medalist fencer Race Imboden knelt as the national anthem played Friday at the Pan American Games in Lima, Peru, to protest racism, gun control, mistreatment of immigrants and President Donald Trump.

“We must call for change,” he tweeted afterward along with a photo. “This week I am honored to represent Team USA at the Pan Am Games, taking home Gold and Bronze. My pride however has been cut short by the multiple shortcomings of the country I hold so dear to my heart. Racism, Gun Control, mistreatment of immigrants, and a president who spreads hate are at the top of a long list.

“I chose to (sacrifice) my moment today at the top of the podium to call attention to issues that I believe need to be addressed. I encourage others to please use your platforms for empowerment and change,” he said.

Imboden, 26, was ranked as the world’s second-best in the foil event, and won a bronze medal in the men’s individual foil on Tuesday. On Friday, he helped the US win gold in the men’s foil team event, and then took a knee on the podium as the Star Spangled Banner played.

As Imboden knelt, his teammates Gerek Meinhardt and Nick Itkin stood tall. Several members of the silver medalist Brazilian team saluted and Canada’s bronze-winning team stood quietly.

Taking a knee during the national anthem became a form of civil protest after former NFL quarterback Colin Kaepernick took a knee throughout the 2016 football season in protest of police brutality and injustice against people of color. Since then, many athletes, from NFL players, to soccer star Megan Rapinoe to amateur high schoolers have knelt as a form of protest, sparking anger from Trump and others.

Imboden was not the only American to protest during the anthem at the Pan American Games. Gwen Berry took gold in the women’s hammer throw competition on Saturday, and she raised her fist in the air at the end of the national anthem in protest.

The US Olympic and Paralympic Committee did not immediately respond to CNN’s request for comment.