The Trump administration on Friday declared the coronavirus a public health emergency in the United States, and announced that certain foreign nationals deemed to pose a risk of transmitting the disease will temporarily be denied entry to the U.S. Some returning American citizens potentially at risk will be quarantined.

Health and Human Services Secretary Alex Azar said that President Donald Trump signed an order for the U.S. to deny entry to any foreign nationals who have traveled in China within the past two weeks, aside from the immediate family of U.S. citizens.

Azar, speaking to reporters at the White House, also said that any U.S. citizens who have been in China's Hubei province — home of Wuhan, the epicenter of the virus — within the last 14 days "will be subject to up to 14 days of mandatory quarantine to ensure they're provided proper medical care and health screening." Also starting Sunday, U.S. citizens returning from other parts of mainland China will also face screenings and two weeks of monitoring and self-quarantine.

The risk to the American public is "low" at this time, said Robert Redfield, director of the Centers for Disease Control and Prevention.

Azar called the measures "fairly incremental" and "appropriate, preventative steps." Yet, officials said they wanted to ensure it would remain a low risk to Americans.