The United States has begun implementing changes to its visa policies that will make it harder for some travelers to enter the country under the Visa Waiver Program (VWP). One result of the changes means certain countries’ nationals are no longer eligible to enter the U.S. under the VWP.

The VWP allows eligible nationals of 38 VWP countries to travel temporarily, for up to 90 days, to the U.S. without a visa. Effective January 21, 2016, changes based on the Visa Waiver Program Improvement and Terrorist Travel Prevention Act of 2015 require certain nationals of VWP countries to apply for a visa at a U.S. embassy or consulate.

Affected persons are nationals of VWP countries who have visited Iran, Iraq, Syria, or Sudan on or after March 1, 2011, and nationals of the VWP countries who have dual citizenship from any of these four countries. Under these changes, a traveler’s currently valid Electronic System for Travel Authorization (ESTA) will be revoked if he or she has previously indicated holding dual nationality with one of these four countries on his or her ESTA application.

An exception exists for those who travelled to one of these four countries for military or diplomatic purposes on behalf of a VWP country. The Act also authorizes the U.S. Department of Homeland Security to grant a waiver on a case-by-case basis if the agency determines that doing so would be in the interest of U.S. law enforcement or national security.