The U.S. State Department issued a travel alert late Monday for Europe, warning of "heightened risk of terrorist attacks... particularly during the holiday season."
"U.S. citizens should exercise caution at holiday festivals, events, and outdoor markets. This Travel Alert expires on February 20, 2017," the alert reads. "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."
Paris is opening a major Christmas market later this week, often a hub for tourists.
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The alert comes a day after French security officials thwarted an Islamic State group plot. France arrested seven people after anti-extremist raids in Strasbourg and Marseilles on Sunday, the interior ministry said Monday. Agence France-Presse reported that the mayor of Strasbourg, Roland Ries, said the interior ministry told him the targets were "in the Paris region" and not in his city.
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Interior Minister Bernard Cazeneuve warned against a "new terrorist attack that had been planned for a long time on our soil" at a news conference in Paris. The ministry says 418 people had been arrested for links to extremist networks since the start of the year.
"European authorities continue to conduct raids and disrupt terror plots," the department alert notes. "We continue to work closely with our European allies on the threat from international terrorism."