Clashes erupted between the Kurdish Workers Party PKK and Jalan Talabani's Patriotic Union of Kurdistan near Suleimaniya in northern Iraq on Wednesday. Some 30 PKK rebels were killed, Turkish and Kurdish reports said.
Kurdish sources said dozens of PUK fighters were killed.
The two sides had last clashed in northern Iraq in October.
Numerous PKK fighters had left Turkey, some for Iraq after jailed PKK leader Abdullah Ocalan, who faces the death penalty, launched a peace appeal earlier this year.
The PKK has charged that Turkey is supporting the PUK in northern Iraq.
According to the Turkish armed forces general staff, the PKK currently has 4,500 fighters, many of whom are no longer in Turkey.
Fighting between Turkish government forces and the PKK has claimed over 32,000 lives since 1984, according to official figures.
Ocalan, who is on death row on the prison island of Imrali, launched a peace appeal in September, calling on Turkey to enter a "peace dialogue" with the Kurds.
(la/dpa)