The ATP and WTA tennis tournament in Indian Wells, California, has been canceled over concerns about the outbreak of the new coronavirus, making it the first major sporting event in the US to be scrubbed due to health concerns.

The tournament, one of the biggest outside the four tennis Grand Slams, was canceled just days before it was due to begin.

Officials said in a news release on Sunday that they opted to cancel after the health ­department of California's Riverside County declared a public health emergency for the Coachella Valley - in the desert east of Los Angeles - after a confirmed case of COVID-19 locally.

Days earlier, organizers had said they planned to go ahead with extra health measures in place such as hand sanitizing 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.

Even before the cancelation the tournament, which draws more than 400,000 fans each year, had offered refunds to anyone who bought tickets but did not want to attend.

Many of the players have already arrived in Indian Wells for the event with qualifying matches scheduled to start on Monday and the main draw set to kick off on Wednesday. 

"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.

"We are prepared to hold the tournament on another date and will explore options," Haas added. 

The number of American coronavirus cases is now at over 500 and involves some 30 US 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.

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 "Fifth Slam."

There is also a men's and women's tournament schedule 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.