The size of the Ukraine flag that a fan had draped around her during a match at the Cincinnati Open on Monday was the reason she was asked to remove it from the grounds, tournament officials told Reuters on Tuesday.
During a qualifying match between Russian players Anna Kalinskaya and Anastasia Potapova on Sunday, one of the players reportedly complained to the WTA chair umpire Morgane Lara about the fan, according to reports.
Video of the incident posted online showed Lara come down from her chair to speak to the fan, who ultimately left the court.
Local 12, an Ohio outlet, reported that the fan was told by the umpire that she was "not being nice" and needed to put the flag away.
She was reportedly approached on the grounds by the tournament's head of security after leaving the match, who told her the flag was above regulation size.
"Per the Western & Southern Open's bag policy, as stated on the tournament's website, flags or banners larger than 18 x 18 are prohibited," a spokesperson for the tournament said.
"Therefore, the patron was asked to remove the flag from the grounds and after doing so was allowed to remain at the tournament.
"Any inquiries about the chair umpire should be directed to the WTA Tour."
The WTA Tour did not respond to a request for comment.
Russia invaded Ukraine on Feb. 24, calling it a "special military operation" aimed at pre-emptively safeguarding its security against NATO expansion. Ukraine and the West accuse Moscow of waging an unprovoked imperial-style war of aggression.
In response, Wimbledon banned Russian and Belarussian tennis players from the grass court major this year.
The U.S. Open, which starts on Aug. 29, will allow players from those countries to compete and will host a tournament-long campaign to raise awareness and humanitarian aid for Ukraine with a goal of raising $2 million in relief, the United States Tennis Association (USTA) said last week.