Security level lowered at Nato Awacs base after intelligence revealed unspecified threat

The security level at a Nato airbase in the German town of Geilenkirchen has been lowered again, according to Nato officials.

Nato Airbase Geilenkirchen, the base housing Nato's fleet of Awacs (airborne warning and control system) surveillance aircraft, was raised on Thursday "based on intelligence information indicating a potential threat".

"The security level at NATO Air Base Geilenkirchen has returned to Bravo+. The temporary rise to Charlie was a precautionary measure to minimise potential risk to our organization and personnel," the air base said.

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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 the AWACS surveillance planes was working with minimal staffing as a precautionary measure, however, operations did continue as planned.

Nato has yet to provide any further 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".

Nato's 'eyes in the sky'

Nato Airborne Early Warning and Control Force is home to Nato's 'eyes in the sky', the E-3A airborne warning and control system (Awacs).

More than a dozen AWACS aircraft are stationed at the Geilenkirchen base.

The surveillance plane's distinctive radar dish makes the Awacs easily identifiable, although the aircraft is in fact a modified, 20th-century Boeing 707, once used by commercial airlines.

It plays an important and unique role in the alliance by protecting Allied airspace.

The aircraft provides the alliance with immediately available air and maritime surveillance, airborne command and control, and air battle management capability.

In recent years, Nato AWACS aircraft conducted flights over Eastern Europe to monitor Russian military activity near the alliance's borders.