Turkey deploys special forces against Kurdish rebels in Iraq
"Operation Claw-Tiger has begun. Our special forces heroes are in Haftanin," the defence ministry tweeted.
"Our commandos, who are supported by combat helicopters and drones, have been transported by our air force," it said.
The defence ministry justified launching the operation due to a "recent upsurge in attacks on our police stations and military bases" near the Iraqi border.
It said the deployment was preceded by an intense artillery bombardment.
The move is likely to increase friction between Ankara and Baghdad, which on Tuesday summoned the Turkish ambassador to protest against Turkish airstrikes on Kurdish rebel positions in northern Iraq this week.
The Turkish military, which regularly carries out operations against the Kurdistan Workers' Party (PKK) in southeast Turkey and its rear bases across the border, on Sunday night launched raids against the northern Iraqi territories of Kandil, Sinjar and Hakurk.
The PKK, which has fought an insurgency against the Turkish state since 1984, is banned as a terrorist group by Ankara and its Western allies.