US President Donald Trump was booed during an NBA Finals game in New York on Tuesday, as his attendance prompted ultra-tight security.Fans jeered the Republican leader, who was watching the game from an executive suite, when he appeared on screen inside the Madison Square Garden arena during the national anthem.Security measures were hiked for the visit, with authorities barring fans without tickets from coming within several blocks of the venue.They also banned watch parties directly outside the Manhattan venue — a break from the first two playoff games between the New York Knicks and the San Antonio Spurs, which drew jubilant crowds.Officials urged ticket holders to arrive at least two hours before the 8.30 pm tip-off to clear airport-style security screening But it's pretty cool he wants to show up and be a part of it," he said.The Knicks, chasing their first basketball championship since 1973, have whipped up a feverish following in the largest US city.Ticket prices for Monday's game were out of reach for most New Yorkers, but the self-proclaimed "World's Most Famous Arena" was still packed to the rafters, with celebrity fans courtside.Among those attending was New York mayor Zohran Mamdani, who told reporters he paid nearly US$1,000 ($1,400) for his tickets.The Secret Service deployed counter-drone technology as part of its operation to protect the US leader, who has faced three alleged assassination attempts in less than two years.Trump, a long-time Knicks fan and native New Yorker, last visited Madison Square Garden in November 2024 to watch a UFC fight after his election victory