An attack could be “highly likely”, the AWACS facility in Geilenkirchen said

The facility in Geilenkirchen, Germany, which hosts special NATO radar planes, has increased its security level due to an intelligence alert about a potential threat.

Geilenkirchen, located near the German-Dutch border, is home to NATO’s AWACS (airborne early warning and control systems) force, which became operational in 1988.

“We have increased the security level at NATO Air Base Geilenkirchen based on intelligence information indicating a potential threat,” the base said on its X (formerly Twitter) account on Thursday night.

“All non-essential mission personnel have been sent home as a precautionary measure,” the added base. “Operations continue as planned.”

The base has reached threat level Charlie, a spokesman told Reuters. That means there has been an incident or intelligence indicating that some type of terrorist attack is underway. “highly likely.”

Geilenkirchen reported an attempted break-in last week that triggered a full security sweep of the base. On the same day, Germany’s Cologne-Wahn air force base was placed on lockdown while authorities investigated reports of contaminated water supplies. Subsequent test results showed no problems with tap water, however.

On Thursday, authorities launched an investigation after unidentified drones were seen flying over critical infrastructure in the northern part of the country.

NATO has stepped up warnings of possible Russian sabotage in recent months, even as it has stepped up supplies of weapons, ammunition and equipment to Ukraine. The United States and its allies have insisted that supporting Kiev does not make them part of the conflict with Moscow, ignoring Russia’s repeated warnings to that effect.