Intense fighting lasted some two hours around the base at Guerbya, near the city of Zakho close to the Turkish border, the witness told AFP.

There was no immediate word from the Turkish authorities.

It was the first reported attack on a Turkish base in Iraqi Kurdistan and came as Turkish troops were in the fourth week of a deadly incursion in the Syrian Kurdish enclave of Afrin.

Guerbya is one of 18 bases in Iraqi Kurdistan that Turkey has maintained since the 1990s despite repeated calls by the region's parliament for them to be removed.

The PKK, which has been waging a deadly insurgency in southeastern Turkey since 1984, also has a significant presence in the region.

"We have reports of an attack by unknown assailants on the Turkish military position at Guerbya at around 8:30 am (0530 GMT)," PKK spokesman Haval Dmaha said.

He said he had "no idea about the identity of the assailants".

The PKK said a number of Turkish soldiers were killed in the attack, but there was no independent confirmation of any deaths.

The witness told AFP that after the attack, Turkish forces bombarded the area.

Turkish troops and allied Syrian rebels launched a major operation in Afrin on January 20 against Kurdish militia of the People's Protection Units (YPG).

Ankara regards the YPG as an offshoot of the PKK and has vowed to end its control of the Syrian border enclave.