For a third time in three days Iran has denied repeated Turkish statements that the two countries are cooperating in a military operation against Kurdistan Workers' Party (PKK).

The Kurdish party, which has been engaged in an armed struggle for autonomy in Turkey's mostly Kurdish southeast since 1984, is listed as a terrorist organization by Turkey, the United States, and the European Union.

On March 19, Turkey repeated its claim from a day earlier that it is carrying out a military operation jointly with Iran against Kurdish separatists, after Iran’s Fars news agency had quoted the military as denying it was involved.

Turkish President Tayyip Erdogan also repeated the claim adding it was the first of its kind and that he hoped further missions would follow.

Iranian Army officials immediately denied Erdogan's comments.

Nevertheless, Turkey's Ministry of Interior issued a statement and repeated Erdogan's claims. Once again, Iran responded by another denial.

Spokesman of the Iranian Armed Forces, Abolfazl Shekarchi, said on Wednesday, March 20, Iran has no plan to hold joint military operations with Turkey at border areas.

Speaking to the Islamic Republic's official news agency, IRNA, on Wednesday, Shekarchi underlined the absence of Iranian forces in a joint operation with Turkey and said the two countries have never had such action at their common borders.

Millions of ethnic Kurds live in the mountainous region along the borders of Turkey, Iraq, Syria, and Iran. Some have links to Turkey's militant PKK, which has for decades fought for an independent homeland.

Iran and Turkey share some 500km (approximately 331 miles) of borders most of which includes mountainous regions.