Clashes between the Iraqi army and Kurdish PKK militia killed two Iraqi soldiers and wounded five of the militants on Sunday, the Iraqi military said in a statement.
The clashes took place in Sinjar in northwestern Iraq after the PKK fighters were denied passage through an army checkpoint, the statement said, adding that the militants drove a vehicle into one soldier and attacked the checkpoint.
The PKK did not immediately comment.
Security incidents pitting the Iraqi military against armed groups other than ISIS are rare.
Sinjar, near the border with Syria, was one of the first areas to be recaptured from ISIS in 2015 during a US-backed campaign to drive the jihadist group out of vast areas they once controlled in Syria and Iraq.
The security situation in the remote mountainous region remains fragile, however, with the presence of a number of different armed groups.
The PKK has fought a decades-long insurgency in southern Turkey but has bases in northern Iraq, including near Sinjar.
Iraqi Shiite Muslim paramilitaries who helped defeat Islamic State are also stationed around Sinjar, as are Iraqi Kurdish Peshmerga forces - PKK rivals who serve the authorities that run northern Iraq’s semi-autonomous Kurdish region.