The attacks by Kurdistan Workers' Party (PKK) rebels on Turkish troops occurred in several locations in Cukurca and Yuksekova in Hakkari province near the Iraqi border, during the night from Tuesday to Wednesday, it said.

The toll is the heaviest for the army since 1993, when the PKK killed 33 unarmed soldiers in Bingol province, in southeast Turkey.

Television reports said the army had initiated an air-supported operation against the rebels in response and the head of the general staff and some commanders had gone to the region.

Authorities are discussing a possible ground operation into northern Iraq, where the rebels fled after the attacks, NTV news channel said, saying the army had used artillery fire against them as they fled.

The death toll might rise as some injured soldiers have sustained life-threatening wounds, NTV said.

"Turkey will not be shaken by terror... We will do whatever we can do to finish this," President Abdullah Gul said in televised remarks.

Prime Minister Recep Tayyip Erdogan has cancelled a trip to Kazakhstan because of the attacks, NTV said.

Clashes between the PKK and the army have escalated since summer.

On Tuesday, a landmine explosion killed five police and three civilians in southeast Turkey in an attack which security sources blamed on Kurdish rebels.

The PKK, listed as a terrorist organisation by Turkey and much of the international community, took up arms in Kurdish-majority southeastern Turkey in 1984, sparking a conflict that has claimed about 45,000 lives.