SALT LAKE CITY — Republican Utah gubernatorial candidate and former ambassador Jon Huntsman Jr. said Wednesday he has tested positive for COVID-19.

Huntsman said he is experiencing “classic symptoms” of the illness caused by the coronavirus, and will isolate himself while his campaign continues.

“Like so many others, my goal is to keep my family safe,” he said in a tweet. “Though isolated temporarily, we’ve never been more energized in this important race for governor. The work goes on!”

The news comes after a campaign staffer tested positive last week.

Huntsman previously served as Utah governor until 2009, when he left to be the U.S. ambassador to China under then-president Barack Obama. He later served as ambassador to Russia under President Donald Trump before resigning and mounting his campaign for governor.

Huntsman, 60, is one of four Republican candidates on the June 30 primary ballot. He is considered a front-runner, though in a tight contest with Lt. Gov. Spencer Cox, who has had a higher profile recently by helping run the state’s response to the coronavirus crisis.

Primary ballots began going out this week in the election being conducted entirely by mail due to the pandemic. It’s the first wide-open governor’s race in Utah in more than a decade.

Huntsman went into quarantine last week and canceled all his public appearances after learning of the staff member’s positive test.

He attended a campaign event in the small northern Utah city of Logan shortly before getting the news. It was held outside to allow for social distancing practices, though a number of people there did not wear masks, the Herald Journal newspaper reported. A photo shows Huntsman shaking hands with an attendee, neither wearing a mask.

The number of coronavirus cases has been trending upward in Utah as the state moves toward re-opening the economy under pressure from conservatives who cite the heavy economic toll of business shutdowns aimed at stopping the spread.

Huntsman’s positive test came after an initial incorrect negative result from the Salt Lake County Health Department. A second test came back positive.

His running mate, Provo Mayor Michelle Kaufusi, was cleared to continue campaigning in person last week.

His daughter Abby Huntsman left her role as a host on the TV show “The View ”to join the campaign. It was not immediately clear if she had been affected by the virus.

The family is among the most well-known in Utah. Jon Huntsman Sr. was a billionaire businessman and philanthropist.

The staffers and their positions have not been identified. Campaign headquarters was closed for cleaning last week and and later reopened.

For most people, the new coronavirus causes mild or moderate symptoms, such as fever and cough that clear up in two to three weeks. For some, especially older adults and people with existing health problems, it can cause more severe illness, including pneumonia and death. The vast majority of people recover.

His other opponents are former state House Speaker Greg Hughes and former GOP chair Thomas Wright.