The ATP and WTA tennis tournament in Indian Wells, California, has been cancelled over fears surrounding the new coronavirus outbreak, making it the first major sports event in the US to be scrubbed due to health concerns.
The tournament, one of the biggest outside the four tennis Grand Slams, was cancelled just days before it was due to begin.
Officials said in a news release on Sunday that they opted to cancel because California health officials had declared a public health emergency for the Coachella Valley - in the desert east of Los Angeles - after a confirmed case of COVID-19.
"We are very disappointed that the tournament will not take place, but the health and safety of the local community, fans, players, volunteers, sponsors, employees, vendors, and everyone involved with the event is of paramount importance," said tournament director Tommy Haas.
Days earlier, organisers had said they planned to go ahead with extra health measures in place such as hand-sanitising stations, beefed-up cleaning protocols and gloves for ball kids, volunteers and food workers.
The ATP and WTA had also issued virus-related guidelines, telling players not to accept items from fans to be autographed.
Before the cancellation, the tournament had offered to give refunds to anyone who had bought tickets, but did not want to attend.
The tournament draws more than 400 000 fans each year to Indian Wells, 27 kilometres southeast of Palm Springs.
Many of the players had already arrived in Indian Wells with qualifying matches scheduled to start on Monday and the main women's draw beginning on Wednesday.
"I'm shook," Canadian tennis star Denis Shapovalov wrote on his Twitter page.
The number of coronavirus cases in the US has exceeded 500 spread across more than 30 states.
California officials are also battling to contain an outbreak on a cruise ship off the coast where 21 people have tested positive for the virus among the 3 500 people on board.
"There is too great a risk, at this time, to the public health of the Riverside County area in holding a large gathering of this size," said doctor David Agus, professor of medicine and biomedical engineering at the University of Southern California.
"It is not in the public interest of fans, players and neighbouring areas for this tournament to proceed. We all have to join together to protect the community from the coronavirus outbreak."
Indian Wells lasts two weeks and draws some of the largest crowds for a tennis event in North America. The number of competitors and lucrative prize money being offered for the men and women has helped earn it the nickname of "The Fifth Slam".
There is also a men and women's tournament scheduled for Miami later this month but there was no word on any changes to that event.
Following Miami, the tours head to Europe for the beginning of the clay court season. The run up to the French Open includes the ATP and WTA event in Rome, Italy, the hardest-hit European country with 366 deaths from the virus.
"It is too soon to speculate about what will happen to other tournaments that follow," WTA chairman Steve Simon said on Sunday. "Health and safety will always come first."
Simon told The New York Times they also considered holding matches without fans but scrapped that idea as well.
"We were supportive of the concept. But ultimately the tournament didn't feel it was in their best interest," he said.
The virus now known as COVID-19 originated in Wuhan, China, late last year and quickly spread across the globe.
The illness affects the respiratory tract and can be transmitted through coughing, sneezing and contact with those infected or with surfaces where the virus is present. Symptoms include fever, coughing and difficulty breathing.
In Italy, the Serie A football season has descended into controversy because of match cancellations and player resistance to competing in empty stadiums.
Among other sports disruptions worldwide, the start of Japan's J-League has been postponed. The Chinese Formula One Grand Prix was cancelled and the Bahrain Grand Prix is set to be held without spectators.
In the United States, the NBA has warned teams to prepare for the possibility of playing games in empty stadiums.
The NHL is also monitoring the outbreak and indicated it wouldn't object if teams choose to limit access to players by media in the locker room.