The ship gives its International Maritime Organization code and destination -- Valencia, Spain -- and sails on.

Five years after the attacks on the United States of September 11, 2001, NATO seamen and airmen continue to patrol the Mediterranean in Operation Active Endeavor of the US-led "war on terror."

"The Mediterranean is safer now," Italian navy Commander Alfonso Citarella told AFP.

The long-range, French-built Breguet Atlantique prop plane was primarily designed for anti-submarine warfare, but adapted easily to its new job, Commander Ezio Lama tells AFP.

The plane carries out visual and electronic reconnaissance of ships plying the Sicily Channel connecting the sea's western and eastern sub-basins during missions lasting between six and eight hours.

In the narrow, unlit cabin the crew huddles in front of the screens as the plane's computers amass data to be transmitted to NATO's southern command in the central Italian port of Naples.

GPS technology instantly locates ships of more than 20 meters within a 300-kilometer radius, giving their names, positions and destinations.

The 32-meter (100-foot) plane also "questions" buoys placed at strategic points to receive the "acoustic signature" -- the unique noise made by the propellers -- of cargo ships sailing in the area.

Each day between 7,000 and 8,000 ships carry merchandise across the Mediterranean, and Active Endeavour assures the security of maritime routes from the Suez Canal in the east to Gibraltar in the west.

Some 30 percent of the world's maritime traffic passes through the sea.

"At any time the deployment includes a minimum of three frigates, one reconnaissance plane and a submarine, without counting national contributions," Citarella said.

"At least 1,200 men are assigned to these tasks every day under NATO," said Citarella, who is responsible for the operational organization of Active Endeavour.

The operation began on September 13, 2001, after NATO invoked for the first time Article 5 of its founding Washington Treaty, which states that an attack on one member is considered an attack on all.

Active Endeavor -- which held a celebration here Friday to mark five years of operation -- has identified more than 83,000 ships, of which "99 percent check out, so we have to concentrate on the remaining one percent," Citarella said.

The mission's remit extends beyond fighting terrorism to cover drugs, arms and people trafficking, piracy and illegal immigration in the Mediterranean as well as clearing World War II land mines from areas near ports.

Many non-NATO members have taken part in the operation including Russia and Ukraine. Information is also exchanged with Albania, Algeria and Morocco.

Related Links
International Maritime Organization
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News and analysis about the Global War Against Terror at SpaceWar.com
Naval Warfare in the 21st Century