BERLIN (Reuters) -NATO has lowered the security level for its base in the German town of Geilenkirchen, it said on Friday, after the state of alert had been raised overnight "based on intelligence information indicating a potential threat".
"The security level at NATO air base Geilenkirchen has returned to Bravo+," NATO said on social media platform X. "The temporary rise to Charlie was a precautionary measure to minimise potential risk to our organisation and personnel. All scheduled operations are proceeding as planned."
Security level Charlie is defined as "an incident has occurred or intelligence has been received indicating that some form of terrorist action against NATO organisations or personnel is highly likely".
The security alert meant the base housing NATO's fleet of AWACS surveillance planes was working with minimal staffing as a precautionary measure while operations continued as planned.
NATO did not give details about the nature of the threat.
Charlie is the second-highest of four states of alert, one level above Bravo+, defined as "an increased and more predictable threat of terrorist attack, which may target NATO installations and personnel".
It was the second time the base raised the security level after an incident last week when a military base in nearby Cologne was temporarily sealed off as authorities investigated possible sabotage of the water supply.
The same day, the base in Geilenkirchen reported an attempted trespassing incident that prompted a full sweep of the premises.
With regard to the suspected sabotage at the base in Cologne, the German military later gave the all-clear, saying test results had shown that tap water was not contaminated.
NATO has warned in the past of a campaign of hostile activities staged by Russia, including sabotage and cyberattacks. Russia has regularly accused NATO of threatening its security.
In June, NATO Secretary-General Jens Stoltenberg said the Western military alliance saw a pattern evolving and that recent attacks were a result of Russian intelligence becoming more active.
Several incidents on NATO territory have been treated as suspicious by analysts in recent years, among them the severance of a vital undersea cable connecting Svalbard to mainland Norway in 2022.