Kurdish rebels killed four soldiers, including a sergeant, in a clash near the city of Sirnak, local authorities said on Sunday.
The rebels also killed another soldier in an overnight attack on a military outpost in Bingol province, deputy governor Fikret Zaman said.
A total of three soldiers were also injured on Sunday.
Zaman said a group of rebels opened fire on a military outpost near the village of Yazkonagi in Bingol early on Sunday, killing a sergeant and wounding two privates. A non-commissioned officer was also injured in the clash in Sirnak.
The rebel attack in Bingol was the first reported direct assault on Turkish troops since the Kurdistan Workers Party, or PKK, declared a one-month ceasefire on 20 August to seek indirect talks with the government.
The government ignored the rebel truce.
It was not clear whether the PKK had decided to end its truce, which was to expire on 20 September.
Sunday's attack followed street clashes between Kurdish protesters and Turkish nationalists around the country.
On Sunday, police rounded up 44 Kurdish protesters, who were shouting slogans in support of the PKK in the city of Sanliurfa, the Anatolia news agency reported.
More than 37,000 people have lost their lives in clashes between Turkish troops and autonomy-seeking Kurdish rebels since 1984.