The Wall Street Journal had previously reported that Israel's Secret Services were preparing to track down and kill Palestinian Hamas leaders around the world after the end of the Gaza war.
Ankara had warned the Jewish state of "serious consequences" if it pursues Hamas inside Turkiye.
Anti-terrorism and intelligence service units raided addresses in Istanbul and the Aegean province of Izmir following an arrest warrant from the Istanbul chief public prosecutor's office, the Anadolu report said.
Two other suspects had separately been arrested previously as part of the same investigation, it added.
The suspects are accused of collecting reconnaissance on potential Mossad targets inside Turkiye via private detectives.
They allegedly sold images and tracking data, among other things, to Mossad, according to Anadolu.
Turkiye has recently ramped up targeting alleged Mossad members inside the country.
Ankara fears Mossad is recruiting operatives on Turkish territory to target foreign nationals, with media reports saying certain Hamas members are in the country. Turkiye maintains links with the Hamas movement.
In January, Turkish police detained 34 people over alleged "political or military espionage" for Mossad, according to Anadolu.
-- BERNAMA
