Eight Turkish soldiers were killed and 15 were wounded on Tuesday in fighting with Kurdish militants in southeast Turkey, security sources said, in the deadliest clashes in recent months.

The fighting broke out in three areas of Hakkari province, which borders Iraq and Iran, and military operations were continuing against the rebels from the Kurdistan Workers Party (PKK) guerrilla group, the sources told Reuters.

The militants were believed to have crossed the border from northern Iraq to carry out the attacks and then retreated back across the border, they said.

Several thousand PKK militants are believed to be based in mountain hideouts in northern Iraq, from where they regularly launch attacks on state targets in mainly Kurdish southeast Turkey.

The PKK, designated a terrorist group by Turkey, the United States and European Union, launched its separatist insurgency in 1984 and more than 40,000 people have been killed in the conflict.