President Donald Trump was greeted with a chorus of boos and chants of “Lock him up!” along with some cheers on Sunday night as he was introduced at Nationals Park in Washington, D.C., during the team’s third World Series home game against the Houston Astros.

Trump, who was there with first lady Melania Trump, stood smiling and clapping throughout.

Some fans broke out into chants of “Lock him up!” after Trump was shown on the stadium’s big screen during a moment to honor a group of Marines.