Kurdistan (1)
Kurdistan Workers Party (PKK) fighters stand in formation in northern Iraq on May 14, 2013. REUTERS/Umit Bektas

Turkey's army killed 35 Kurdish militants after they attempted to storm a base in the southeastern Hakkari province early on Saturday, military officials said.

The overnight attack came hours after clashes in Hakkari's Cukurca district between soldiers and militants from the Kurdistan Workers Party (PKK) that left eight soldiers dead, the officials said.

The militants attempted to take the base in three different groups, but were spotted by aerial reconnaissance. An air operation was launched, killing 23 of them, the officials said.

Four more were then killed in a ground operation, they said. The remaining eight were killed in clashes in Hakkari's Cukurca district.

Friday's clashes in Cukurca also left 25 soldiers wounded, the officials said.

Turkey's military - NATO's second-largest - is grappling with the insurgency in the mainly Kurdish southeast as its senior ranks undergo a major shake-up in following a July 15-16 coup attempt.

On Thursday, Turkey announced an overhaul of the armed forces, with 99 colonels promoted to the rank of general or admiral and nearly 1,700 military personnel given dishonourable discharges over their alleged roles in the coup.

About 40 percent of all generals and admirals in the military have been dismissed since the coup.

In the southeast, the military has frequently carried out air strikes after a 2 1/2-year ceasefire and peace process between the government and the PKK broke down last summer.

Thousands of militants and hundreds of civilians and soldiers have been killed since then. Some cities in the predominantly Kurdish southeast have been engulfed in the worst violence since the 1990s.

More than 40,000 people have been killed in the conflict since the PKK - designated a terrorist group by Turkey, the United States and the European Union - began its insurgency in 1984.