Turkey launched air strikes in northern Iraq on Kurdish militants planning an attack, the army said on Tuesday, just days after Ankara began an offensive against a Kurdish militia in Syria.

The strikes took place on Monday in the Zap region of northern Iraq, not far from Turkey's southeastern border, the Turkish military said in a statement.

The army said it was targeting members of the "separatist terrorist organisation" -- Turkey's official term for the outlawed Kurdistan Workers' Party (PKK).

The militants were planning an attack on border security posts and bases, the military said, adding that the strikes destroyed weapons emplacements and shelters.

The PKK has been waging an insurgency against the Turkish state since 1984, and is blacklisted as a terror group by Ankara and its Western allies.

After a two-year ceasefire collapsed in 2015, the Turkish army intensified its military operations against the PKK in the Turkish southeast.

The Turkish air force has regularly carried out raids on PKK rear bases around the Qandil mountains in northern Iraq since then.

Turkish troops also sometimes stage ground incursions into the area.

The strikes in Iraq come four days after Turkey started a military operation, supporting Syrian rebels, against the Syrian Kurdish People's Protection Units (YPG) militia in a bid to remove it from its western enclave of Afrin in northern Syria.

Ankara views the YPG as an offshoot of the PKK and repeatedly calls them "terrorists".