ISLAMIC cleric Fethullah Gulen has said a crackdown on his followers by Turkish Prime Minister Tayyip Erdogan was "10 times worse" than anything meted out after coups by the secularist military.

Mr Erdogan has accused Mr Gulen's Hizmet network, which has built quiet influence in the police and judiciary over decades, of orchestrating a fraud investigation which has grown into one of the biggest challenges of his 11-year leadership.

He has responded by tightening government control of the courts and reassigning thousands of police officers and hundreds of prosecutors and judges, in what his aides say is a drive to cleanse the judiciary of Mr Gulen's influence.

In his first interview in Turkish media since the scandal burst into the open in December, the US-based cleric, whose worldwide network of followers claim to number in the millions, said he was the victim of a campaign of slander.

He added: "What we are seeing today is 10 times worse than what we saw during the military coups. This inflicts extra pain on us. All we can do is remain patient."