By Steve Keating
NEW YORK (Reuters) - The U.S. Open stepped up security for the men's semi-finals on Friday after environmental activists disrupted a women's match a day earlier, halting play for nearly an hour.
The United States Tennis Association (USTA) said additional police had been stationed around Arthur Ashe Stadium with undercover officers in the stands ahead of the first of Friday's two singles contests between Serbian thee-time champion Novak Djokovic and young American Ben Shelton.
Four climate protesters, wearing shirts with the slogan 'End Fossil Fuels' forced the stoppage of a match between Coco Gauff and Karolina Muchova on Thursday when they began shouting in the upper bowl of Arthur Ashe Stadium, the sport's largest venue with a seating capacity of over 23,000.
As players stood staring into the stands, security and New York City police entered the section where the disturbance was taking place.
Three of the four protesters were removed peacefully but a fourth had glued his feet to the concrete floor, causing a 49-minute delay in play before he was escorted out of the stadium in handcuffs and taken into custody.
When play resumed Gauff went on to claim a 6-4 7-5 win over Muchova and a spot in Saturday's final.
The environmental group Extinction Rebellion (XR) took responsibility for the protest, warning in a statement, "no tennis on a dead planet! If we don't disrupt, nature will."
The group pointed out that it was not protesting tennis, but the use of fossil fuels.
"We're not protesting the event itself; we are not protesting tennis; we are not protesting the emissions that brought spectators to get here," said Shayok Mukhopadhyay, Extinction Rebellion activist. "That's not the point.
"We are here because we have to disrupt this public event as our last resort to draw public attention to the climate emergency we are facing today."
After her match Gauff said she had no animosity for the protesters and believed that climate change was real.
Extinction Rebellion later posted on social media site X, formerly known as Twitter: "Congratulations to Gauff on her victory."
Several major sporting events have been targeted by climate groups this year. 'Just Stop Oil' protesters interrupted play at Wimbledon in July, releasing orange ticker-tape mixed with jigsaw puzzle pieces during matches.
The second Ashes cricket test at Lord's, the Premiership Rugby final, the World Snooker Championship, golf's British Open and the Grand National horse race have also witnessed climate protests this year.
(Reporting by Steve Keating in New York. Editing by Toby Davis)