A Chicago Cubs fan who appeared to flash a "white power" hand gesture behind a black sports reporter while he was on air has been banned from Wrigley Field.

The Cubs sweatshirt-wearing fan's face couldn't be seen during the Tuesday NBC Sports broadcast of the Cubs' home game against the Miami Marlins. But his hand, which appeared in a frame behind analyst Doug Glanville, was positioned in the “OK" hand gesture, often associated with the white supremacist movement.

The fan, who has not been identified, was "indefinitely" banned from Wrigley Field for violating the Chicago Cubs Guest Code of Conduct, the team's president of business operations, Crane Kenney, said in a statement Wednesday.

"If he attempts to enter Wrigley Field or other ticketed areas he may be subject to prosecution for criminal trespass to property," the statement said.

Kenney said earlier Wednesday that the club was investigating the incident "because no one should be subjected to this type of offensive behavior."

"Such ignorant and repulsive behavior is not tolerated at Wrigley Field," Kenney said.

Kevin Cross, the senior vice president of NBC Sports Chicago said the network was "disappointed by the incident that took place on our air ... one that was at the expense of our colleague Doug Glanville."

"We find the behavior of this fan reprehensible and clearly does not represent the great Cubs fans of our city and those around the country," Cross said.

Glanville thanked NBC Sports and the Chicago Cubs organization for launching an investigation. "They have displayed sensitivity as to how the implications of this would affect me as a person of color," he said in a statement.

The "OK" hand gesture only recently emerged as a "white power" symbol.

That new meaning stems from a hoax by members of the website 4chan to "falsely promote the gesture as a hate symbol, claiming that the gesture represented the letters 'wp,' for 'white power,' according to the Anti-Defamation League (ADL).

The hoaxers hoped "the media and liberals would overreact by condemning a common image as white supremacist," the ADL says.

But "by 2019, at least some white supremacists seem to have abandoned the ironic or satiric intent behind the original trolling campaign and used the symbol as a sincere expression of white supremacy," according to the ADL.

The ADL cautions that because the sign once had only an innocuous meaning, "particular care must be taken not to jump to conclusions about the intent behind someone who has used the gesture."