Here is the link to the actual warning the US State Dept. has published:
https://travel.state.gov/content/passpor...alert.html
Here is the text at that link:
Europe Travel Alert LAST UPDATED: MAY 31, 2016
As part of the State Department’s continuous efforts to provide Americans travelling abroad with information about relevant events, we are alerting U.S. citizens to the risk of potential terrorist attacks throughout Europe, targeting major events, tourist sites, restaurants, commercial centers and transportation. The large number of tourists visiting Europe in the summer months will present greater targets for terrorists planning attacks in public locations, especially at large events.
This Travel Alert expires August 31, 2016.
France will host the European Soccer Championship from June 10 – July 10. Euro Cup stadiums, fan zones, and unaffiliated entertainment venues broadcasting the tournaments in France and across Europe represent potential targets for terrorists, as do other large-scale sporting events and public gathering places throughout Europe. France has extended its state of emergency through July 26 to cover the period of the soccer championship, as well as the Tour de France cycling race which will be held from July 2- 24.
The Catholic Church’s World Youth Day event is expected to draw up to 2.5 million visitors to Krakow, Poland, between July 26 and July 31. U.S. citizens should be aware that local infrastructure may be strained due to the large number of visitors. Poland will impose border controls at all of its national borders from July 4 to August 2, and visitors to Poland during this period should be prepared to show their passport and undergo stricter security screening throughout Poland. More information to help prepare for travel to World Youth Day can be found at
https://pl.usembassy.gov/world-youth-day-2016/ and
https://travel.state.gov/content/passpor...thday.html.
U.S. citizens should also:
Exercise vigilance when in public places or using mass transportation.
Be aware of immediate surroundings and avoid crowded places.
Follow the instructions of local authorities, especially in an emergency.
Monitor media and local event information sources and factor updated information into your travel plans and activities.
Be prepared for additional security screening and unexpected disruptions.
Stay in touch with your family, have a plan if you are separated and ensure they know how to reach you in the event of an emergency.
European authorities continue to take steps to assure public safety and disrupt terrorist plots. We work closely with our allies and will continue to share information with our European partners that will help identify and counter terrorist threats.
For further information:
See the State Department's travel website for the Worldwide Caution, Travel Warnings, Travel Alerts, and Country Specific Information.
Enroll in the Smart Traveler Enrollment Program (STEP) to receive security messages and make it easier to locate you in an emergency.
Call 1-888-407-4747 toll-free in the United States and Canada or 1-202-501-4444 from other countries from 8:00 a.m. to 8:00 p.m. Eastern Standard Time, Monday through Friday (except U.S. federal holidays).