Irish people will have to submit to being fingerprinted and photographed to enter the United States from October. New security measures announced in Washington have added the US's closest allies to a list of countries already affected by the rules.
Under the current regulations, only tourists who need a visa have to submitto the procedures. Travellers from a further 27 nations, including Ireland, Japan, Britain and Australia, are now included.
Annoucing the measure in Washington, Homeland Security Department Undersecretary Asa Hutchinson said that the new measures would increase security.
'It will allow us to check against our terrorist criminal watchlist those foreign visitors who are traveling from Visa Waiver Program countries', the undersecretary said.
Citizens from the 27 states have been generally permitted to visit the US without a visa for up to 90 days for pleasure or business, and only required visas to study or work legally.
The move has caused anger and has triggered retaliatory measures from some nations. Brazil now fingerprints US visitors, and China has said it will require some US citizens seeking Chinese visas to appear for interviews.