The US State Department has warned citizens traveling to Europe to take caution because of the growing threat for terrorist attacks particularly during the holidays. Travelers should stay clear and be vigilant at large public crowds especially at famous tourist landmarks, events, and outdoor markets.

"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 and associated events," stated the State Department's website.

Travelers are advised to be watchful of their surroundings as these "extremist sympathizers" might execute their attacks with no warning, using "conventional and non-conventional weapons." Terrorists could employ reckless and suicidal tactics similar to what happened in the Nice attack at France on July where more than 80 persons were killed.

"If you are traveling between countries in Europe, please check the website of the U.S. Embassy or consulate in your destination city for any recent security messages," the State Department warned.

According to Independent, the terrorist group's web magazine that promotes extremist terrorism acts, Rumiyah stated that the holidays are perfect to conduct terror acts. It provided the Macy's Thanksgiving Parade as an example stating that it would be an 'excellent target'.

Travelers to Europe should be aware of local information sources and follow local authorities. European authorities are conducting strict security screenings which travelers should be prepared for.

The State Department also advises US citizens to enroll in their Smart Traveler Enrolment Program (STEP) where they can be informed for travel alerts and warnings.

"European authorities continue to conduct raids and disrupt terror plots.  We continue to work closely with our European allies on the threat from international terrorism," the stated affirmed.