An Iranian semi-official news agency is reporting that members of the elite Revolutionary Guard have detained several suspects it says are linked to the Islamic State group in clashes in the country's northwest.

The Fars news agency's Saturday report says the Guard members clashed with 21 fighters suspected of being linked to IS who entered the country through its western border. The report did not elaborate.

The remote mountainous majority-Kurdish areas near the borders of Iraq and Turkey are the scene of occasional clashes between Iranian forces and IS-linked fighters and militant Kurdish separatists.

Iran said on Wednesday that it had seized a large supply of ammunitions from a separatist group in the area.