Cruise ship passengers disembarking at US ports are now banned from flying home on scheduled airline services.
The Department of Homeland Security and Centers for Disease Control and Prevention announced the restriction which covers all passengers and crew, even those not showing any signs of coronavirus symptoms.
Passengers and crew members may only fly on chartered aircraft or by private transport.
A government official said there would be various exceptions under specific circumstances such as foreign nationals who would need to take scheduled flights out of the country.
The fear is of cruise passengers unwittingly spreading the virus during a flight home.
After several days of negotiations a Holland America ship with thousands of passengers and crew was disembarked in Fort Lauderdale, Florida, and passengers were allowed to fly home on commercial airliners.
The first line to be impacted by the new rule is Princess Cruises.
"Princess Cruises is working around the clock to arrange small group charters and individual car transport for its U.S. guests to comply with the updated CDC guidelines," a Carnival Corp spokesperson said.
The US Coast Guard said there are more than 100 ships in or near US territorial waters carrying about 93,000 crew members.
