This afternoon the State Department issued an initial security reminder via Twitter, with an expanded version expected early next week.

Travel - State Dept @TravelGov

Holiday Security Reminder: Remain aware of your surroundings and exercise caution in places with large crowds. Extremists continue to focus on locations such as holiday markets, shopping malls, clubs, restaurants, places of worship, transportation hubs, festivals, and events.

Additional information will be provided in this weekend's issue of the AlertsUSA Threat journal newsletter.