Mr Gulen was speaking to the BBC in his first broadcast interview in 16 years.
He was responding to allegations he had ordered his followers holding senior positions in the police and judiciary to launch those investigations.
Mr Gulen heads the Hizmet movement.
Hizmet, which means "service", promotes a tolerant form of Islam, emphasising education, altruism and hard work and attracts millions of followers, extending its influence far beyond Turkey.
Since arriving in the US in the late 1990s, Mr Gulen, 74, has not given a single broadcast interview. But now, the BBC has had exclusive access to the Muslim cleric”
The Turkish prime minister has accused Mr Gulen, a
one-time ally who lives in self-imposed exile in the US, of trying to attack the
government. Four ministers have resigned in the aftermath of the corruption
inquiries.
Mr Erdogan has condemned the investigation as a "dirty plot" by Gulen supporters to overthrow him.
But Mr Gulen, 74, told the BBC that the reactions of the ruling AK Party - which have included sacking a number of police commissioners and the arrest of some of Mr Erdogan's allies - were anti-democratic.
Fethullah Gulen Turkish Islamic cleric"These moves were made to make our movement appear bigger than it already is and to frighten people about this non-existent phantom threat”
Of Hizmet's alleged direct involvement in the corruption
investigations, he said that some of the demoted, sacked or reassigned members
of the police and judiciary "were not linked to us".
"These moves were made to make our movement appear bigger than it already is and to frighten people about this non-existent phantom threat."
But many people - academics, newspapers and diplomats - have suggested that it is inconceivable that Mr Gulen did not give the direct order for the net to close in on Mr Erdogan's allies, particularly after Mr the prime minister had moved to close down Hizmet schools in Turkey, says the BBC's Tim Franks who interviewed Mr Gulen at his home in Pennsylvania.
"It is not possible for these judges and prosecutors to receive orders from me. I have no relation with them. I don't know even 0.1% of them," Mr Gulen told the BBC.
"People in the judiciary and the police carried out investigations and launched this case, as their duties normally require."
"Apparently they weren't informed of the fact that corruption and bribery have ceased to be criminal acts in Turkey," he added, with what our correspondent describes as a tinge of sarcasm.
The Hizmet movement
- Hizmet ("service") is the Turkish name of what is commonly known as the Gulen movement
- The movement is inspired by the teachings of Islamic preacher Fethullah Gulen, who lives in exile in the US
- There is no formal structure but its followers are numbered in the millions
There was a time when there was a clear overlap in
ambition between the apparently mild Islamic approach of this cleric, and the
apparently mild Islamism of the AK Party under Mr Erdogan, Tim Franks says.
But there seem to be equally clear signs of divergence now, for example over Mr Erdogan's embrace of peace talks with armed Kurdish separatists, led by jailed leader Abdullah Ocalan.
Mr Ocalan, according to Mr Gulen, was "uneasy with what we were doing with the Kurdish people" (through the extension of Hizmet schools deep into Kurdish territory).
"They didn't want our activities to prevent young people joining the militants in the mountains. Their politics is to keep enmity between Kurdish and Turkish people."
The establishment of schools and investment in the region "were regarded as if they were against the peace process".
Asked of the heightening of tensions between Turkey and Israel in recent years, Mr Gulen said: "They try to portray us as a pro-Israeli movement, in the sense that we have a higher regard for them than our nation.
"We are accepting them as a people, as part of the people of the world."
Source: Read the full article here: http://bit.ly/Gulen_BBC2