Turkish military outposts are often the target of PKK rebels
Turkish troops in pursuit of Kurdish rebels have crossed into northern Iraq and killed four militants, Turkish officials say.
The military said air strikes were also launched against rebel positions deeper inside Iraqi territory.
The offensive took place after rebels made an unsuccessful attack on border guards, Turkish officials said.
Turkey has been fighting insurgents of the Kurdish Workers Party (PKK) for more than a quarter of a century.
Military officials said three commando companies and one special forces battalion penetrated 3km (two miles) into Iraq in pursuit of the rebels.
The PKK is fighting for autonomy in Turkey´s largely Kurdish south-east.
The group is considered a terrorist group, not just by Turkey but by the US and the EU.
More than 40,000 people are believed to have died in the conflict, on both sides.