The NATO airbase in the German town of Geilenkirchen has raised its security level "based on intelligence information indicating a potential threat".
"All non-mission essential staff have been sent home as a precautionary measure," the base said in a statement late Thursday.
A spokesperson for the base in Geilenkirchen said the threat level had been raised to Charlie, the second highest of four states of alert, which is defined as "an incident (that) has occurred or intelligence has been received indicating that some form of terrorist action against NATO organizations or personnel is highly likely."
The authorities did not provide any details but assured there was no reason for concern and that security had been raised as a precautionary measure.
