GEILENKIRCHEN, Germany -- NATO troops who will operate AWACS radar surveillance aircraft left for Turkey on Monday as part of a mission to protect the country in the event of a war with Iraq, NATO officials here said.

The troops, whose number was not revealed, departed from the NATO base at Geilenkirchen, near Aachen in Western Germany.

AWACS aircraft are to move to Konya, Turkey - some 220 kilometers (140 miles) south of Ankara -- this week, Major General Johann-Goerg Dora, commander of the NATO AWACS fleet, told reporters.

Initially two aircraft will be used but the number is expected to double in due course, NATO officials said last week. All 17 of NATO's AWACS planes are based in Germany. Dora said the mission in Turkish airspace near the Iraqi border would be "purely defensive."

"We will not allow ourselves to get involved in an offensive operation," Dora said.

NATO last week approved the deployment of a package of measures to boost Turkey's defenses after a crisis within the alliance sparked by opposition from three European countries.

France, Germany and Belgium had blocked NATO from initiating military planning, arguing that it would send the "wrong signal" while diplomacy continues in a bid to disarm Iraq of weapons of mass destruction.

AWACS (Airborne Warning and Control System) is an early-warning system used to detect enemy air activity and to coordinate friendly aircraft involved in interception or attack.

Beyond the AWACS, NATO is also sending Patriot missile systems and chemical-biological response units to Turkey.

Germany opposes a war against Iraq but it has said that it will allow U.S. and NATO forces unfettered access to their bases and its airspace.