"A small-scale operation conducted by ground troops as part of hot pursuit... dealt a heavy blow," the general staff said in a statement on its website late Tuesday.

The troops penetrated "several kilometres" into northern Iraq from the southeast Turkish province of Hakkari, which also borders Iran, it said.

The statement did not indicate how many troops took part in the incursion, which it said began overnight after the army "received images" of a group of Kurdistan Workers' Party (PKK) militants attempting to sneak across the border.

The military also said it would continue cross-border operations in line with a Turkish parliamentary authorisation in October that approved such incursions to clamp down on the PKK, which has long taken refuge in Kurdish-run northern Iraq.

"The Turkish armed forces will continue to fulfill its responsibilities," the statement said.

Northern Iraqi officials has said earlier about 500 Turkish troops crossed into remote areas in northern Iraq and began withdrawing Tuesday afternoon.

The incursion followed Turkish air raids Sunday on positions in northern Iraq along the Turkish frontier and in the Qandil mountains to the east, where the PKK is known to have camps.