General Metin Gurak, the head of the general staff's press department, said that intercepted wireless communication between Kurdistan Workers' Party (PKK) rebels during Tuesday's operation in Sirnak province spoke of up to 35 casualties.

"As you can see the organisation has suffered heavily. We are still sweeeping the area. We do not have an official statement yet" on the PKK's losses, he told a press conference.

The communication was intercepted after Turkish artillery and gunship fire targeted two groups of PKK militants when they were moving towards a military outpost in the mountainous region, he said.

The intercepeted messages also suggested the the rebels might have shot dead fellow militants who were seriously wounded and could not move.

The Turkish army has intensified operations against the PKK since October 3 when the militants crossing from hideouts in neighbouring Iraq assaulted a border outpost, killing 17 soldiers.

Beside operations inside Turkey, it has carried out seven air raids against PKK camps in northern Iraq, including one in which senior PKK members were targeted in the mountainous region of Zap, a major rebel stronghold.

The PKK, listed as a terrorist group by Ankara and much of the international community, took up arms for Kurdish self-rule in the southeast in 1984, sparking a conflict that has claimed about 44,000 lives.

Turkey's parliament last week extended by one year the government's mandate to order cross-border military strikes against the PKK in northern Iraq, which has been in effect since October 17, 2007.

Turkish officials estimate about 2,000 PKK rebels are holed up in the mountains of northern Iraq, where they allegedly enjoy free movement and obtain weapons and explosives for attacks in Turkey.