A charter flight from Wuhan, China, carrying approximately 200 U.S. citizens, taxis to a stop at March Air Reserve Base in Riverside, Calif. Wednesday morning Jan. 29, 2020. Will Lester | Inland Valley Daily Bulletin via Getty Images

U.S. health officials have quarantined 195 Americans evacuated from Wuhan, China, taking the rare step of issuing a mandatory order for the first time in more than 50 years to help contain an outbreak of a new coronavirus that's spread to roughly 10,000 people across the globe. "CDC under statutory authority of the HHS secretary has issued federal quarantine orders for all 195 passengers," Dr. Nancy Messonnier, director of the National Center for Immunization and Respiratory Diseases, said on a Centers for Disease Control and Prevention conference call with reporters Friday. "While we recognize this is an unprecedented action, we are facing an unprecedented public health threat."

Trump administration officials later said they were and issuing mandatory quarantines for any U.S. citizens who have visited Hubei province, where Wuhan is located, in the last 14 days. Travel restrictions were also being issued for anyone who visited elsewhere in mainland China over the previous two weeks. The administration plans to deny entry to foreign nationals who "pose a risk of transmitting" the virus in the U.S., administration officials said at a news conference a few hours after the CDC's call. "Any U.S. citizen returning to the United States who has been in the Hubei province in the previous 14 days will be subject to up to 14 days of mandatory quarantine to ensure they're provided proper medical care and health screening," Health and Human Services Secretary Alex Azar said. The new coronavirus, which was discovered about a month ago, can spread before symptoms show, Messonnier said, citing a new report from the New England Journal of Medicine. The illness has quickly spread throughout mainland China, with 7,000 new cases confirmed over the last week and at least 213 deaths. World health officials previously said the virus is transmitted through human contact, in droplets released by coughing or sneezing and even by touching surfaces with germs. The last time U.S. health officials issued a mandatory quarantine was in the 1960s during a smallpox outbreak, they said.

"We are preparing as if this were the next pandemic but we are hopeful still that this is not and will not be the case," she said, adding that the tests for the virus aren't foolproof. "This is a very serious public health situation and CDC and federal government has and will continue to take aggressive action to protect the public." The passengers will be quarantined at the March Air Reserve Base in Riverside County, California, during the incubation period, or 14 days, she said. They arrived in the U.S. from Wuhan on Wednesday and were screened multiple times and monitored throughout the flight, health officials said. Messonnier said Wednesday that the CDC has 20 staff on hand to monitor their health. If any of the passengers begin to exhibit symptoms, they will be moved to a hospital, she said. Messonnier said the goal of the quarantine is to prevent "as much as possible community spread" of the coronavirus. "This is one of the tools in our toolbox to mitigate the potential impact of this novel virus on that United States," she said. "We are preparing as if this were the next pandemic, but we are hopeful still that this is not and will not be the case." Messonnier said the respiratory disease can be carried through droplets or through sneezing and coughing, confirming what World Health Organization officials told reporters earlier this week.