[DEVELOPING STORY] WASHINGTON—U.S. President Donald Trump has ordered a travel ban between the U.S. and mainland Europe for 30 days beginning Mar. 13 for foreign nationals, in a stunning move aimed at limiting the spread of COVID-19. 

The “presidential proclamation ... suspends the entry of most foreign nationals who have been in certain European countries at any point during the 14 days prior to their scheduled arrival to the United States,” a Department of Homeland Security statement said. 

Affected countries are Austria, Belgium, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Italy, Latvia, Liechtenstein, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden and Switzerland--collectively the Schengen Area.

The ban "does not apply to legal permanent residents, (generally) immediate family members of U.S. citizens, and other individuals who are identified in the proclamation,” the statement added.  

"The United States government is unable to effectively evaluate and monitor all of the travelers continuing to arrive from the Schengen Area," the proclamation said. "The potential for undetected transmission of the virus by infected individuals seeking to enter the United States from the Schengen Area threatens the security of our transportation system and infrastructure and the national security"

The country list does not include the U.K. and its massive London Heathrow hub. It could also be lifted early, Trump said, depending on circumstances.

“Anything coming from Europe to the United States is what we are discussing,” Trump said in a televised address Mar. 11 from the White House. Officials later clarified that cargo and goods are not part of the ban, which is similar to restrictions in place with China and Iran.

Trump said there will be “exemptions” for people “who have undergone appropriate screenings.” He did not provide details. 

For most airlines, the ban adds to a painful downturn created by COVID-19’s spread. Flights through major hubs such as Frankfurt and Paris will presumably be affected.  

It also raises questions on how such a ban would be enforced. London Heathrow, a major hub that links continental Europe and the U.S., is not affected by the ban. Nor are routings through Canada, which has grown as a choice for travelers who need to connect through a major hub en route between the U.S. and Europe.

Airlines said they were working to meet the new restrictions.

"We are in contact with the federal government to understand and comply with this directive," American Airlines said.