The State Department issued a travel warning on Monday urging U.S. citizens to be vigilant while attending holiday festivals, events, and outdoor markets in Europe over the next few weeks due to a heightened risk of terrorist attacks.
The updated alert came one day after French authorities arrested seven people on Sunday during anti-terror raids in Strasbourg and Marseilles, CNN reported. Interior Minister Bernard Cazeneuve said Monday the arrests effectively thwarted "a new terrorist attack that had been planned for a long time on our soil."
The State Department warned Americans that "credible information" suggests the Islamic State, al Qaeda, and affiliates are planning terrorist attacks against European targets, particularly as the holiday season approaches.
"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," the State Department said. "Terrorists may employ a wide variety of tactics, using both conventional and non-conventional weapons and targeting both official and private interests."
French investigators believe ISIS-linked operatives in Syria were plotting to attack the Strasbourg Christmas market, which opens Friday and is expected to bring in two million visitors. Authorities are seeking to determine whether some of those arrested on Sunday had traveled to Syria through Cyprus.
Cazeneuve heeded that the terrorist threat in France had never "been so high."
ISIS claimed responsibility in July for the truck attack that killed 86 people in Nice during Bastille Day celebrations. The attack marked one of the largest of several in France in less than two years. Terrorist attacks over the past year have killed more than 200 people in France, according to the Wall Street Journal.