Istanbul - Turkish police detained 26 security officers on Tuesday on suspicion of illegally wiretapping politicians, civil servants and businessmen, Dogan News Agency reported.
The raids were a further salvo in President Tayyip Erdogan's campaign against supporters of his ally turned arch-foe, the U.S.-based Muslim cleric Fethullah Gulen.
The chief prosecutor's office in the western coastal city of Izmir carried out the raids, according to Dogan, a privately owned national news service.
Prosecutors were not immediately available for comment.
Erdogan accuses Gulen of setting up a "parallel state" within the Turkish administration and trying to topple him, blaming his supporters within the police and judiciary for a corruption inquiry that rocked the government late in 2013.
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In the course of the scandal, apparently incriminating wiretap recordings of the then-prime minister, ministers and other senior officials were leaked onto the Internet.
Erdogan has cast the investigation, which led to the resignation of three ministers, as a "coup attempt" and in response he had thousands of police officers, judges and prosecutors removed from their posts.
Last month a Turkish court issued an arrest warrant against Gulen on suspicion of heading up a criminal organisation. Gulen, who lives in self-imposed exile but was for years an important Erdogan ally before their relations soured, denies any involvement in plots against the government.