US change entry requirements
As a reaction to the attacks in Paris, the US decided on new regulations regarding entry of tourists, focused on the so called "Visa-Waiver" programm. 23 EU Member States, including Austria, and 15 further countries with strong boundaries to the US participate in this programm that allows citizens of those countries to stay in the States for a maximum of 90 days without a visa.
In order to enter the US, they only needed a positive response of the Electronic System for Travel Authorization (ESTA). For most travellers, nothing will change. The questionnaire of ESTA was extended and applicants will be asked about former stays abroad. Everyone who travelled to Syria, Iraq, Iran or Sudan in the past five years will have to apply for a visa from now on.
Another requirement for travelling without a visa will be a forgery-proof passport with biometric information. In Austria, such passports are produced since 2009 and include the scan of a fingerprint.
Background: The US government intends to prevent that EU citizens that travelled to one of the above mentioned countries on the purpose of terroristic activities (like getting in touch with the Islamic State or receive a respective training) could entry the US without a visa or comprehensive check-up.
The article "Crisis, war, terrorism" provides further information.