Dr. Carlos del Rio, an infectious disease expert, and other Emory University experts are set to hold an online press conference Wednesday morning urging government officials and business leaders to make masks mandatory.

With a sense of urgency, the call for immediately requiring masks be mandatory comes as the number of coronavirus cases soars in Georgia, and days before the July 4th holiday when people often crowd together to celebrate.

Del Rio, who is also executive associate dean of Emory University School of Medicine at Grady Health System, and Dr. Jonathan Lewin, CEO of Emory Healthcare, will also discuss other recommended preventive measures, such as frequent hand washing and social distancing, to help reduce the spread of the virus.

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Savannah on Tuesday became the first major city in Georgia to require the use of face masks, setting up a potential showdown with Gov. Brian Kemp over whether local officials can take more sweeping steps than the state to contain the coronavirus.

Savannah Mayor Van Johnson’s emergency order requires people to don face masks when in many public places starting at 8 a.m. on Wednesday. Violators will be offered a face covering before they are cited, Johnson said, and fined $500 if they flout the requirement.

“Frankly, and honestly, I do not believe we have any other choice,” Johnson said Tuesday at a briefing at Savannah City Hall, pointing to rising numbers of confirmed coronavirus cases in the coastal Georgia city. “The numbers speak for themselves. These are not the numbers Savannah wants or needs to break.”

The governor’s office didn’t comment on Johnson’s decision. If Kemp attempts to block Savannah’s order, it could set up a thorny legal and political battle. If not, it could clear the way for Atlanta other cities to take similar steps.

MORE: In split with state, Savannah's mayor requires face masks

Atlanta Mayor Keisha Lance Bottoms is among the local officials who have called for stricter rules.

Pressed recently on whether he'll impose a requirement for masks, Kemp said he believes a requirement to don face-coverings is a “bridge too far” and expressed concern about a lack of widespread public support.

MORE: Kemp to embark on a 'wear a mask' tour of Georgia

Meanwhile in Savannah, Johnson’s order requires people entering a commercial establishment in the city to wear a face-covering or mask, though it exempts religious establishments and makes exceptions for people under 10 years old and those eating, drinking or smoking. It also doesn’t cover people exercising while outside, so long as they’re socially-distanced.