International visitors who are not required to obtain a visa to enter the United States will be asked additional questions, Secretary of Homeland Security Jeh Johnson said in a statement on Monday.
"The new information sought includes additional passport data, contact information, and other potential names or aliases," Johnson said.
The Washington Post reports the changes came about because authorities are concerned about people who hold Western passports but may have become radicalized.
The Post reports:
"For the first time, U.S. officials said, such travelers will be required to disclose whether they hold passports from multiple countries, or have previously used alternate names or aliases — data that can enable more accurate screening against U.S. terrorism watch lists. ...
"U.S. officials said the changes were driven by concern over how many citizens from 'visa-waiver' countries have fought in Syria and, because of their citizenship, hold passports that enable them to travel relatively freely across Europe and potentially to the United States. Many have joined an affiliate of al-Qaeda or a rival group, the Islamic State, that has seized territory and executed American and British hostages."
Under the State Department's Visa Waiver Program citizens of 37 countries are allowed to enter the United States simply by completing an online form.