The soldiers were captured by rebels from the outlawed Kurdistan Workers' Party (PKK) during an ambush on October 21 on a military unit in Turkey's southeast, near the border with Iraq, which also left 12 troops dead and 17 injured.

They were released on November 4 after being held captive for two weeks in northern Iraq, were arrested by a military court a week later and went on trial Friday in the eastern town of Van.

No details were given of the trial proceedings, the military having clamped a bar on reporting "in the interests of national security."

The prosecution was demanding a life sentence against one of the soldiers on several charges including "collusion in a crime against the state's unity and territorial integrity" and "persistent insubordination resulting in great loss".

The soldier, a Kurd, had reportedly been accused by his commanders of being the first to surrender to PKK rebels and encouraging his friends to follow his example and lay down arms.

The remaining seven troops risk a jail term of up to five years for disobeying orders.

The October 21 ambush shocked Turkey and put pressure on the Ankara government to take military action in northern Iraq to root out PKK rebels using the region as a springboard for attacks across the border in Turkey.

The PKK, blacklisted as a terrorist group by Ankara and much of the international community, has been fighting for Kurdish self-rule in Turkey's mainly Kurdish southeast since 1984 in a conflict that has claimed more than 37,000 lives.

Turkey has carried out four air strikes against PKK positions in northern Iraq since December 16 as well as a ground cross-border operation to stop a group of rebels trying to infiltrate Turkey.

Iraqi Kurds, who run northern Iraq, reported two other air strikes in December that Ankara did not confirm.