With fears mounting about the coronavirus threat the Democratic National Committee announced Tuesday that Sunday's first head-to-head presidential debate between former Vice President Joe Biden and Sen. Bernie Sanders will take place without an audience.

The announcement came a day after party and city officials said they would be following the guidance of local officials, but that there were no plans to cancel the debate. Biden's and Sanders' campaigns asked the DNC to dispense of the audience, according to a written statement Tuesday from the DNC.

“At the request of both campaigns and out of an abundance of caution, there will be no live audience at the Arizona debate taking place on Sunday, March 15th," DNC communications director Xochitl Hinojosa said in a statement. "The DNC has been in regular communication with local health officials and the Mayor's office, which advised that we could proceed as planned. Nevertheless, our number one priority has and will continue to be the safety of our staff, campaigns, Arizonans and all those involved in the debate. We will continue to remain in daily contact with all stakeholders through Sunday.”

CNN announced that at the request of the campaigns and out of an abundance of caution, it was also eliminating the planned spin room and the press filing center.

By eliminating the audience component, debate organizers allay health concerns and minimize the potential for grandstanding by supporters on either side.

The decision essentially means that Biden and Sanders will be debating to a large, empty room at the Arizona Federal Theatre, the downtown venue long known as Comerica Theatre.

The decision could add a more sober tone to a debate in which many pundits think Sanders needs to stand out to reverse his flagging fortunes.

The announcement came hours after Sanders and Biden scrapped planned rallies in Cleveland, Ohio, after a trio of the COVID-19 virus were confirmed in that state. Each campaign said they would consider canceling future campaign events, as well.

Arizona's count of presumed positive and confirmed new coronavirus cases remains at six, but testing for the virus is increasing.

CORONAVIRUS IN ARIZONA:Where the virus is now, symptoms, travel safety

As of Tuesday morning, the state had tested 84 people for the virus, which means 28 additional tests were done in the past day.

The venue seats an estimated 5,000 people, said a spokesman for Arizona's Democratic Party.

The debate is sponsored by CNN and Univision and in partnership with CHC Bold, the political arm of the Congressional Hispanic Caucus.

The debate is set for two days before the end of voting during the state's presidential primary, technically known as the presidential preference election, so it will likely have little impact on the final outcome in Arizona.

Still, by holding such an event in Arizona, the party is showing how competitive the state has become as a presidential battleground. Democrats have only carried Arizona in presidential elections once since 1948.

As alarm over the new coronavirus’ rapid spread grew in Arizona and worldwide, Democratic and local officials told The Republic on Monday they were taking precautions to minimize spread at the debate, which would have brought together a large gathering of the candidates’ campaign teams, the public and reporters in downtown Phoenix.

Annie DeGraw, a spokeswoman for Phoenix Mayor Kate Gallego, told The Republic on Monday that officials with the city, county, state, public health, the airport, the Democratic National Convention, CNN, Phoenix Convention Center and the theater "are in daily contact ... to discuss precautions being taken against COVID-19."

Have news to share about Arizona's U.S. senators or national politics? Reach the reporter on Twitter and Facebook. Contact her at yvonne.wingett@arizonarepublic.com and 602-444-4712.

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