The State Department on Monday issued a Europe-wide travel alert throughout the holiday season and into mid-February, based on the "heightened risk of terrorist attacks" then.
"Credible information indicates the Islamic State of Iraq and the Levant (ISIL or Da'esh), al-Qa'ida, and their affiliates continue to plan terrorist attacks in Europe, with a focus on the upcoming holiday season and associated events," the department warned.
"U.S. citizens should also be alert to the possibility that extremist sympathizers or self-radicalized extremists may conduct attacks during this period with little or no warning," it added. "Terrorists may employ a wide variety of tactics, using both conventional and non-conventional weapons and targeting both official and private interests."
After attacks in Belgium, France, Germany and Turkey, the department said it "remains concerned about the potential for attacks throughout Europe."
"If you are traveling between countries in Europe, please check the website of the U.S. Embassy or consulate in your destination city for any recent security messages," it said.
The alert expires Feb. 20, 2017.
