San Francisco on Tuesday declared a state of emergency over the deadly Chinese coronavirus after a top public health official warned its spread across the United States was inevitable and could dramatically impact Americans’ everyday life.

San Francisco Mayor London Breed said in a statement that while the city does not have any confirmed cases, “the global picture” regarding the virus’ spread is “changing rapidly” and officials need to increase its “preparedness.”

“We see the virus spreading in new parts of the world every day, and we are taking the necessary steps to protect San Franciscans from harm,” Breed added.

The declaration will allow officials to mobilize city resources, expedite emergency planning and facilitate future reimbursement at a state and federal level.

Dr. Grant Colfax, director of the San Francisco Department of Public Health, said the move will also boost the number health workers, including nurses and case managers, to assist with a possible outbreak in the city

“It allows us to look at things like shelters and other opportunities for us to expand in the event that that’s necessary and do a broader assessment of the city’s capacity to respond in the event that there is an outbreak of coronavirus in San Francisco,” said Colfax.

As of Wednesday, 53 cases coronavirus cases have been confirmed in the U.S., including 10 cases in California.

Dr. Nancy Messonnier, director of the Centers for Disease Control and Prevention’s (CDC) National Center for Immunization and Respiratory Diseases, warned Tuesday that the virus’ spread across the country is all but certain.

“As more and more countries experience community spread, successful containment at our borders becomes harder and harder,” Messonnier told reporters.

“It’s not a question of if this will happen but when this will happen and how many people in this country will have severe illnesses,” she added. “Disruption to everyday life might be severe.”

President Donald Trump on Monday said that the illness is “very much under control” in the U.S. and that the CDC and World Health Organization (WHO) are “working hard and very smart” to combat it. The president took to Twitter Wednesday to blast the establishment media and Democrats for exaggerating the danger of the illness.

“Low Ratings Fake News MSDNC (Comcast) & @CNN are doing everything possible to make the Caronavirus look as bad as possible, including panicking markets, if possible. Likewise their incompetent Do Nothing Democrat comrades are all talk, no action. USA in great shape! he tweeted.

President Trump also said he will deliver a press conference at 6 p.m. EST to address his administration’s response to the outbreak.