President Donald Trump received a mixed reaction from fans when he attended Game 3 of the NBA Finals at Madison Square Garden on Monday night.

Donald Trump, who was there to watch his hometown New York Knicks, became the first sitting U.S. president to attend an NBA Finals game. But before tipoff, it was his appearance on the arena’s Jumbotron that quickly became one of the night’s biggest talking points.

As the national anthem played, cameras showed Trump saluting. Boos could be heard from parts of the crowd, though the president appeared unfazed by the reaction. Rather than acknowledge them, he smiled and continued saluting throughout the performance.

The atmosphere inside Madison Square Garden shifted moments later when the camera turned away from Trump and focused on Knicks star Jalen Brunson. The boos were replaced by loud cheers, according to VT.

Donald Trump at the NBA Finals
Trump watched the game from a suite owned by Knicks owner Jim Dolan. He was joined by several members of his administration.

The president’s visit also resulted in increased security measures around Madison Square Garden. Fans entering the arena were required to comply with a strict no-bag policy and pass through TSA-style security screenings.

The added security reportedly affected plans outside the venue as well. NBC New York reported that a watch party planned near the arena was canceled, while a secure zone around Madison Square Garden restricted both vehicle and pedestrian access in parts of midtown Manhattan.

Despite the negative reaction from some sections of the crowd during the national anthem, Trump showed no visible response, smiling and maintaining his salute as boos echoed through the arena.