The arrests come at a time of heightened regional tensions over fears of a possible US military strike on Iran.
Authorities in Turkey have detained six people suspected of spying for Iran's Islamic Revolutionary Guard Corps by monitoring military facilities and other strategic sites across the country, domestic media reported on Wednesday.
Security forces carried out simultaneous raids in five provinces including Istanbul and Ankara following a joint investigation by the counter-terror department and Turkey's intelligence agency, state-run TRT television reported.
The suspects, including an Iranian citizen, allegedly conducted reconnaissance and surveillance around Incirlik air base in the southern province of Adana, which hosts US forces, said the broadcaster.
One of the six detainees was of Iranian origin, the private DHA news agency reported.
The group is accused of transmitting intelligence and logistical information to Iranian intelligence operatives, TRT said.
Investigators also reportedly uncovered evidence the suspects had monitored the shipment of drones through Turkey for use in other countries. The Iranian Embassy in Ankara has yet to comment on the arrests.
The arrests come at a time of heightened regional tensions over fears of a possible US military strike on Iran.
Turkish government officials have warned against foreign interference in neighbouring Iran, saying any military operation could lead to "instability" and trigger a "refugee influx".
US President Donald Trump said earlier on Wednesday "a massive armada" is heading towards Iran, warning Tehran it should negotiate.
"It is moving quickly, with great power, enthusiasm and purpose," Trump wrote in a post on his Truth Social platform without giving further details of its mission.
"Hopefully Iran will quickly 'come to the table' and negotiate a fair and equitable deal – no nuclear weapons – one that is good for all parties," he added.
Washington has moved the USS Abraham Lincoln and several guided missile destroyers into the region, which can be used to launch attacks from the sea.