U.S. European Command is calling on troops, family members, and civilian employees to watch for suspicious behavior on and off military installations and to cover their digital tracks while moving around Europe.

Branded “See Something, Do Something,” the initiative is meant “to foster a proactive mindset” toward security and force protection, the command said this week. The announcement comes amid heightened concern about drone incursions and other hybrid threats to U.S. and allied military forces around Europe.

The initiative emphasizes protecting U.S. personnel and their families “as a shared responsibility vital to sustaining long-term combat readiness alongside global partners.” It encourages members of U.S. military communities to stay alert while in crowded public areas, like transit hubs, and report any “unusual behavior or unattended items” to military police or local authorities.

Troops and their families are also “urged” to practice “rigorous digital discipline” by reviewing their social-media privacy settings, disabling geotagging on fitness apps and mobile devices, and avoiding posting information about their locations and travels online. The announcement also cites a recommendation from security experts to vary daily commuting routes, travel times, and off-base activities “to reduce predictability.”

U.S. personnel and their families “are our most precious asset, and their safety is our highest priority,” Gen. Alexus Grynkewich, commander of U.S. European Command, said in the announcement. “By embracing a proactive security mindset and enhancing collective vigilance, we build a stronger force protection environment that keeps us safe and ready.”

European Command did not identify a specific threat that prompted the campaign, but it comes amid increased concern about “hybrid warfare,” — malign activity below the threshold of war that often lacks a clear perpetrator — involving Russia and targeting U.S. forces and NATO allies.

Russian misinformation and intimidation directed against U.S. military personnel and their families using social media and hacking has been a longstanding concern. But since Russia’s 2022 invasion of Ukraine, that hybrid activity has become more aggressive and disruptive. A number of undersea pipelines and cables have been affected by what Western officials believe to be sabotage; GPS jamming and spoofing are more frequent, and drone incursions around sensitive sites, like military bases and airports, have increased.

In September, Germany accused Russia of orchestrating a failed attack with explosive-laden drones at the Leipzig/Halle Airport, which is a key logistical hub for Western supplies to Ukraine. Later in September, a tip about suspicious vehicles near the airbase RAF Fairford led to the arrest of several men in relation to a suspected terrorist plot in which British officials say Iran may have been involved. The incident prompted the US to remove the B-1 bombers that were stationed at the base.

In October, after the discovery of a drone with a canister of explosives near another German airbase, the German military raised its Russian sabotage threat assessment to “substantial” — its second-highest level — and warned that the threat was no longer confined to facilities where Ukrainian troops were being trained and to major military installations. More than 30,000 U.S. military personnel are stationed in Germany.