US President Donald Trump became the first sitting American president to attend an NBA Finals game on Monday, but his historic appearance at New York's Madison Square Garden was met with loud boos from sections of the crowd as he watched Game 3 between the New York Knicks and the San Antonio Spurs.

Trump is making a rare trip back to New York City as president to cheer for them in Game 3 of the NBA Finals against the San Antonio Spurs on Monday night.

The president watched the game from the owner’s box alongside Knicks owner James Dolan and a few other members of his cabinet.

Crowd boos erupted as Donald Trump appeared on the big screens.