CNN reported Sunday that several U.S. military bases in Europe had detected terror threats on the continent.

A spokesman for U.S. European Command, Cmdr. Dan Day told CNN that USEUCOM is "constantly assessing a variety of factors that play into the safety of U.S. military community abroad. As part of that effort, we oftentimes take additional steps to ensure the safety of our service members. For operational security reasons we will not get into specific measures, but we remain vigilant."

The U.S. Army garrison in Stuttgart, Germany, where USEUCOM is headquartered, raised its alert level to Force Protection Condition "Charlie" on Sunday. In its report, CNN noted it is "not clear what intelligence triggered the heightened security."

Nonetheless, in light of the Paris Olympics in July and the European soccer championships in Germany, both countries are said to be putting in place active security measures. Germany is planning to roll out an additional wave of police officers, and France is also said to be taking precautionary measures.

"French authorities actively monitor terrorist threats from organized groups and radicalized individuals," the U.S. Embassy in France said.  "Attacks may happen with little or no warning, targeting tourist locations, major sporting and cultural events, and other public areas that attract large numbers of civilians."

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