Washington on Monday revoked visa-free entry to the United States for foreigners who have visited North Korea.
Visitors who have travelled to North Korea since March 1, 2011 are no longer eligible for entry to the United States.
The U.S. allows citizens of 38 countries to visit the U.S. 90 days without a visa under a waiver programme.
The change will affect tens of thousands of people from visa waiver countries.
U.S. citizens have been banned from visiting North Korea since 2017.