The Izmir prosecutor's office issued an arrest warrant on Saturday for two on duty military admirals and four majors as part of a military spying investigation.

One of the majors was detained in Istanbul on Saturday and was transferred to a court in the western province of Izmir.

Two rear admirals and three majors could not be detained as they received sick reports.

One of the admirals is reportedly on duty in the United States, the other in Ankara.

The military spying investigation was launched in Izmir upon claims that Gülenist linked military personnel were fabricating evidences.

Gülenists are accused of establishing a terrorist organization, which was allegedly behind two coup attempts in 2013. Since the coup attempts through Gülenist sympathizers in judiciary and police were foiled, the group has been targeted in a nationwide purge to stop their influence in the judiciary, police and bureaucracy.

Initially a simple religious group, the Gülen Movement, named after the U.S.-based cleric, turned into a powerful movement controlling business conglomerates and schools in Turkey and around the globe. Gülen is the prime suspect in multiple cases where he and his followers are accused of illegal wiretapping, money laundering and plotting to imprison critics.