Protesters with the words "End Fossil Fuels" on their shirts interrupted a U.S. Open semifinals match between Coco Gauff and Karolina Muchova Thursday.
The incident occurred early in the second set with Gauff leading the match 6-4, 1-0.
U.S. Open tournament referee Jake Gardner entered the court while security went into the stands to remove the protesters. A total of four protesters were taken into custody.
One protester had glued their shoes to the floor of Arthur Ashe Stadium.
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Fans cheered as police arrived. Spectators were asked to move away to clear the area for authorities.
In the midst of of it all, Gauff was seated on her bench eating fruit out of a container and then got up to hit a few practice serves. Muchova had a visit from a trainer. Eventually, the two headed toward the locker room as the delay continued.
The United States Tennis Association released a statement after the match was over.
"Following the first game of the second set in the Gauff-Muchova match, play was halted due to a protest conducted by four spectators," the United States Tennis Association said in a statement.
"Three of the four protesters were escorted out of the stadium without further incident. The fourth protester affixed their bare feet to the floor of the seating bowl. Due to the nature of this action, NYPD and medical personnel were needed in order to safety remove this individual from the stadium.
"The four protesters were taken into NYPD custody."
The organization said 49 minutes elapsed before play resumed.
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Gauff won the match to advance to the U.S. Open final for the first time.
The Associated Press contributed to this report.