Turkish prosecutors have ordered the arrest of 85 staff from the energy and education ministries targeted by an investigation into a failed coup last year.
No further details were given, according to Reuters, which said the news was reported by broadcaster CNN Turk on Tuesday ( 16 May).
Gulen, leader of an Islamic religious and social movement known as the "Gulen movement", or "Hizmet", denied the allegations.
The failed attempt to overthrow the Turkish government was followed by a crackdown on Gulen's supporters in the country. An estimated 120, 000 people were fired from their posts following the failed coup.
Following an April referendum that granted President Recep Tayyip Erdogan sweeping new powers, the country has suspended at least 14,000 civil servants, police and military personnel.
Erdogan, who is currently in Washington to visit US President Donald Trump, is seeking Gulen's extradition.
The Gulen movement was originally on good terms with Erdogan's Justice and Development Party (AKP), as both groups advocate a moderate version of Islam.
However, AKP later labelled Himzet as a terrorist organisation and accused its members of trying to infiltrate the state to overthrow the government. Gulen has been leading Hizmet from the US, where he is in self-imposed exile.
Last August, Turkey submitted a request to the US government to extradite Gulen, who lives in Pennsylvania.
In October that year, Gulen's brother, Kutbettin Gulen, was arrested in the city of Izmir. He was wanted over charges of membership in and leadership of a terrorist organisation.