Four Turkish soldiers were killed and one was injured in two separate clashes with Kurdish rebels on Thursday in the southeast of the country, the Anatolia news agency reported.
Three soldiers were killed in the fighting with members of the outlawed Kurdistan Workers Party (PKK) during an operation in a rural area near the town of Dortyol in Hatay province, the provincial governor's office said, Anatolia reported.
A massive operation has been launched to locate the rebels, it added.
One soldier was killed and another was injured in another attack carried out by PKK members targeting a military unit near the town of Semdinli in Hakkari province, said Anatolia.
The PKK, listed as a terrorist organisation by Turkey and by much of the international community, took up arms in Kurdish-majority southeastern Turkey in 1984, sparking a conflict that has claimed some 45,000 lives.
Fighting usually escalates in spring as snow melts along the mountainous Iraqi-Turkish border, enabling rebels holed up in rough terrain to launch attacks more easily.