A Turkish drone strike killed one member of the Kurdistan Workers Party (PKK) and wounded two others as they were holding a meeting in a refugee camp in northern Iraq on Monday, the region's counter-terrorism service said.
Separately, two other PKK members died in clashes with Turkish forces north of Dohuk, a city in the same region about 40km (25 miles) from the Turkish border, two security sources told news agency Reuters.
The PKK - which is designated a terrorist group by Turkey, the United States and the European Union - took up arms against Turkey in 1984, with the initial aim of creating an independent Kurdish state.
It has since moderated its goals to seeking greater Kurdish rights and limited autonomy in southeast Turkey.
The drone struck a PKK meeting in Makhmour camp, the counter-terrorism service said. Ankara has said the camp housing thousands of Kurdish refugees from Turkey is a haven for Kurdish operatives.
The sources said the clashes took place on Monday in the Mount Gara area, a base for the PKK that has come under Turkish attacks over the past two months.
Ankara regularly carries out airstrikes on PKK militants in northern Iraq and has dozens of outposts in the Iraqi territory.
The PKK is not designated a terrorist organisation in Iraq, but Iraqi authorities have banned it from launching operations against Turkey from their territory.