World number one Ash Barty will skip the U.S. Open and the tournament preceding it in New York due to concerns over the coronavirus pandemic.
"My team and I have decided that we won't be travelling to the U.S. for the Western and Southern Open and the U.S. Open this year," the Australian said in a statement issued by her manager on Thursday.
"I love both events so it was a difficult decision but there are still significant risks involved due to COVID-19 and I don't feel comfortable putting my team and I in that position.
"I wish the USTA all the best for the tournaments and look forward to being back in the U.S. next year."
The Western and Southern Open, which is held annually in Cincinnati, has been moved to New York this year and is set to start in mid-August.
The U.S. Open kicks off on Aug. 31 and will be held in its usual home in Flushing Meadows, Queens, but will be played without fans in attendance to limit the spread of the virus.
The reigning French Open champion will decide later whether to defend her title at Roland Garros starting in late September.
"I will make my decision on the French Open and the surrounding WTA European tournaments in the coming weeks," she said.
World number one Novak Djokovic and 23-times Grand Slam champion Serena Williams are among players expected to compete at the U.S. Open despite concerns about undergoing mandatory quarantine when travelling to Europe, which would have them miss tournaments in Madrid and Rome ahead of the French Open.
Deaths from COVID-19 surpassed 150,000 in the United States on Wednesday, more than any other country and nearly a quarter of the world's total, according to a Reuters tally.
(Additional reporting by Rory Carroll in Los Angeles, editing by Ed Osmond & Shri Navaratnam)
