The New York Knicks and the Philadelphia 76ers each banned a fan and apologized for actions directed at opposing players during playoff games Wednesday.
The Knicks said they banned a man for spitting on Atlanta Hawks guard Trae Young during Game 2 at Madison Square Garden.
"We investigated the matter and determined that this patron, who is not a season ticket holder, did indeed spit on Trae Young, and for that reason, he is now banned from The Garden indefinitely," the Knicks said in a statement. "We apologize to Trae and the entire Atlanta Hawks organization for this fan's behavior."
The behavior "was completely unacceptable and will not be tolerated in our venue," the Knicks said, adding that they had forwarded information to authorities.
New York City police said a complaint had not been filed as of Thursday afternoon.
The 76ers said a fan who threw popcorn on Washington Wizards guard Russell Westbrook as he departed the court in the fourth quarter after an injury at the Wells Fargo Center would have his season tickets revoked. He was also banned from all events at the arena.
The 76ers called the behavior "unacceptable and disrespectful" and said there is no place for it in the sport or the arena.
Neither team released the names of the fans who were involved.
NBA arenas recently started allowing fans to return at or near full capacity.
Westbrook told reporters after the game that the behavior of some fans was worsening.
"This s--- is getting out of hand, especially for me," he said. "The amount of disrespect, the amount of just fans just doing whatever the f--- they want to do. It's just out of pocket, man."
Westbrook said that in any other setting, such incidents wouldn't occur. A man wouldn't come up to him on the street and pour popcorn on his head, he said, because "he knows what would happen."
Young's father, Rayford, said things needed to be brought under control.
Los Angeles Lakers forward LeBron James called on the NBA to protect its players.
"By the way WE AS THE PLAYERS wanna see who threw that popcorn on Russ while he was leaving the game tonight with a injury!!" James tweeted. "There's cameras all over arenas so there's no excuse!"
The NBA said Thursday that "an enhanced fan code of conduct will be vigorously enforced" going forward.
"The return of more NBA fans to our arenas has brought great excitement and energy to the start of the playoffs, but it is critical that we all show respect for players, officials and our fellow fans," the league said.