All entrants to South Korea from the United States are now subject to stricter quarantine measures, as South Korea grapples with a surge in imported cases of the coronavirus.
As of midnight, passengers from the U.S. who do not show symptoms, such as a fever will still be required to self-isolate for two weeks.
Those who show symptoms will be required to take tests upon arrival.
The new measures apply to South Korean nationals and foreign travelers.
South Korea has already been enforcing the same system for all long-term arrivals from Europe, regardless of their symptoms.