BERLIN -- Security at a NATO air base in western Germany has been raised because of intelligence information pointing to a “potential threat,” and all staff not essential to missions have been sent home as a precaution, NATO said.

Geilenkirchen air base, situated near the Dutch border, houses the alliance's Airborne Warning and Control System, or AWACS, aircraft.

A post on the NATO AWACS fleet's X account late Thursday evening, announcing that “we raised the security level,” provided no details regarding the nature of the potential threat. It stated that “operations continue as planned.”

According to dpa, a German news agency, a reporter observed police vehicles at the air base. While police confirmed their presence on Thursday evening, they provided no specific details or further information on Friday morning.

Last week, a significant German air force base near Cologne was placed under lockdown for several hours due to concerns about potential tampering with its water supply. An investigation failed to uncover any evidence of such sabotage. There were also reports of suspicious activity at Geilenkirchen, and an individual was detained for questioning near the base, as reported by dpa. However, these incidents were ultimately deemed harmless.

These incidents occur amidst anxieties concerning the potential vulnerability of infrastructure to potential Russian sabotage .

On Thursday, prosecutors in Flensburg, located in northern Germany, revealed an investigation into suspected espionage aimed at sabotage, without disclosing any specifics about the alleged perpetrators. German media reported sightings of drones over a chemical park in Brunsbuettel, situated on the North Sea coast.