The U.S. State Department issued an alert for summer travel to Europe, citing
the continued threat of terrorist attacks "on tourist locations,
transportation hubs and markets/shopping malls" as well as hotels and
restaurants.
"U.S. citizens should exercise additional vigilance in
these and similar locations, in particular during the upcoming summer travel
season when large crowds may be common," the May 1 alert said.
The alert said that recent incidents in France, Russia,
Sweden and the United Kingdom "demonstrate that the [Islamic State] and
their affiliates have the ability to plan and execute terrorist attacks in
Europe," and that although local governments continue counterterrorism
operations, "the Department nevertheless remains concerned about the
potential for future terrorist attacks. U.S. citizens should always be alert to
the possibility that terrorist sympathizers or self-radicalized extremists may
conduct attacks with little or no warning."
Terrorist tactics include using firearms, explosives,
vehicles as ramming devices and sharp-edged weapons that are difficult to
detect prior to an attack, the alert said.