US military raises terror alert at European bases: Reports

Multiple U.S. military bases in Europe are under a heightened state of alert for a terrorist attack against U.S. military personnel or facilities, multiple media outlets reported Sunday.

The bases include the U.S. Army garrison in Stuttgart, Germany, where the U.S. European Command headquarters is located, which raised its alert level to Force Protection Condition "Charlie" on Sunday, two U.S. officials told CNN.

This level is raised "when an incident occurs or intelligence is received indicating some form of terrorist action or targeting against personnel or facilities is likely," per the U.S. Army.

When reached for comment, U.S. European Command (USEUCOM) said it is "constantly assessing a variety of factors" related to the safety of the U.S military abroad.

"As part of that effort, we often times take additional steps to ensure the safety of our service members," USEUCOM said, adding it will not get into specific measures for "operational security reasons."

"As always, USEUCOM advises personnel in the European theater to remain vigilant and stay alert at all times, including reporting suspicious activity, monitoring Department of State travel advisories, and implementing prudent personal risk mitigation measures," it added.

One of the U.S. officials, who stationed at a European base, told CNN they have not seen this threat level "in at least 10 years," adding it often means military received an "active-reliable threat."

Independent military publication Stars and Stripes, which first reported the development, said similar alerts were sent to other bases in Germany, including the Army’s Rheinland-Pfalz and Ramstein Air Base. The alert for the Rheinland-Pfalz garrison also included Baumholder and outlying installations in Romania and Bulgaria.

Aviano Air Base, located in Italy, saw its condition rise to level Charlie, and other installations in Italy had enhanced security measures, per Stars and Stripes.

ABC News also reported the shift in terror threat, citing two U.S. officials.

It was not immediately clear the nature of the intelligence that reportedly prompted the heightened security.