Six Turkish soldiers were killed on Friday in a clash with Kurdish militants in the southeast of the country while two more lost their lives when a military helicopter sent to the scene crashed, the army said.

Six Turkish soldiers were killed on Friday in a clash with Kurdish militants in the southeast of the country while two more lost their lives when a military helicopter sent to the scene crashed, the army said.

The six troops were killed and eight others wounded in fighting with members of the outlawed Kurdistan Workers' Party (PKK) near a military base in the Cukurca district of Hakkari province.

A Kobra helicopter dispatched to the scene then crashed due to a technical problem, resulting in the deaths of the two pilots, the army added.

Turkish F-16 jets, helicopters and drones were scrambled to fight the "terrorists" behind the attack and reinforcements were sent to the area.

So far, six PKK militants have been "neutralized" in the follow-up operations which are continuing, the army said.

In a separate operation in the neighboring Sirnak province, 15 PKK members have been killed, the army said.

Turkey has been waging an offensive against the PKK after the collapse in 2015 of a two-year ceasefire declared by the group.

Hundreds of members of the Turkish security forces have been killed in attacks since then but President Recep Tayyip Erdogan has vowed no let-up in the operations.

On Thursday night, four PKK militants said to have been loading explosives onto a stolen truck were killed in a huge explosion in an area near Diyarbakir in the southeast that was felt throughout city.

The explosives detonated prematurely, the interior ministry said.

That incident came hours after at least eight people including soldiers were injured by a remotely-detonated car bomb aimed at a military vehicle in Istanbul.

There was no immediate claim of responsibility for the car bomb.