During the holiday season, the U.S. military is advising Americans and their families stationed in Europe to stay safe in public areas.

“Service members, civilians and family members are encouraged to be extra vigilant around areas of public transportation, such as train stations and airports, as well as celebrations that attract large crowds,” U.S. European Command said in a holiday message.

There are no specific threats being made against the U.S. military community. Ever since the Nov. 13 Paris attacks, American servicemen in Europe have been cautioned to look out for suspicious activity and be on the alert when in highly concentrated areas. The last terror attempts in Europe–including the terror attacks in Paris, the attempted beheading in London and the thwarted train hijacking–took advantage of crowded public events and unguarded transportation.

Local police in France and Germany are beefing up their own security details during the coming weeks.

“People should report any suspicious activity to the military police, local police, or your service’s investigative division,” EUCOM said.