"A total of nine mortar shells fell on Turkish territory when Iran launched gunfire Sunday night in an anti-terrorist operation against targets in the north of Iraq," the Hakkari province governorate said in a statement.

It added that Iranian border authorities, who held talks with their Turkish counterparts Monday, confirmed that five people from the Party of Free Life of Kurdistan (PJAK) died in the attacks.

The shells landed "in error" in a remote rural area near the town of Yuksekova in Hakkari province which borders Iran and Iraq. There were no injuries, the statement said.

Another source said the incident happened after Iranian security forces opened fire on positions of the PJAK, an Iranian Kurdish separatist group which has launched attacks on Iran from rear-supply bases in northern Iraq.

Turkish soldiers were investigating the incidents on their side of the border, while Iranian forces were carrying out a similar probe on their side, the source, who did not want to be named, added.

PJAK is closely allied with the PKK, which also uses northern Iraq to launch similar attacks against Turkey in its 24-year campaign for self-rule.

The Turkish army also carries out air raids against PKK positions in the Kurdish-held enclave or targets the rebels with artillery.

Some 45,000 people have been killed since 1984 when the PKK, blacklisted as a terror group by the European Union and the United States, took up arms for autonomy in Turkey's Kurdish-majority southeast.