Turkish police detained five individuals accused of spying for Iranian intelligence in a coordinated operation across multiple cities, authorities confirmed Friday.

The Istanbul Chief Public Prosecutor’s Office announced that the arrests took place in Istanbul, Antalya, and Mersin as part of a joint investigation by Turkish security forces and the National Intelligence Organization (MIT). 

The detainees include three Turkish citizens and two foreign nationals, though officials did not disclose their nationalities.

According to Turkey’s state-run Anadolu Agency, the suspects were allegedly engaged in “military and political espionage.” Authorities believe they gathered intelligence on military bases and strategically significant locations in Turkey and abroad, which they then transmitted to Iranian intelligence operatives. 

The investigation also indicated the suspects had communicated with members of Iran’s Islamic Revolutionary Guard Corps (IRGC) intelligence division.

The detentions come at a time of growing tensions between Turkey and Iran. Turkish Foreign Minister Hakan Fidan recently criticized Iran’s use of regional militias in Syria, calling the policy destabilizing and warning of potential repercussions. “If you are attempting to destabilize a third country, other nations may reciprocate by supporting groups within your own borders,” Fidan said earlier this month. The remarks prompted both countries to summon each other’s diplomats.

Espionage cases linked to Iran have surfaced in Turkey multiple times in recent years. In September 2022, Turkish authorities arrested four Iranian citizens in Istanbul for alleged espionage, forgery, and human trafficking. Earlier in June 2022, Turkish and Israeli intelligence services foiled an alleged Iranian plot to kidnap and assassinate Israeli tourists in Istanbul, leading to the detention of several Iranian and Turkish operatives.