ANKARA, April 30 (Reuters) - Turkish prosecutors have launched a criminal investigation into U.S.-based Islamic cleric Fethullah Gulen based on allegations he attempted to overthrow the government, broadcaster CNN Turk and other media reports said on Wednesday.
Prime Minister Tayyip Erdogan said on Tuesday he would ask the United States to extradite former ally Gulen, whom he accuses of plotting to topple him and undermine Turkey with concocted graft accusations and secret wire taps.
A move to extradite Gulen, whose followers say they number in the millions, would be possible only if Turkey first issued an arrest warrant and produced evidence of a crime, according to one legal expert.
Erdogan, whose ruling AK Party traces its roots to political Islam, accuses him of building a "parallel state" of followers in institutions such as the police and judiciary and using them in an attempt to seize the levers of state power.
Culture Minister Omer Celik told broadcaster NTV there was an investigation into Gulen based on "serious allegations, a process extending as far as spying activities".
NTV reported separately, without specifying its sources, that the investigation, launched by state prosecutors in the capital Ankara, was also based on accusations against Gulen of "establishing and leading a gang", NTV reported.
Officials at the prosecutor's office declined to comment on the reports regarding Gulen, who has lived in self-imposed exile in Pennsylvania since 1999, when secularist authorities raised accusations of Islamist activity. (Reporting by Gulsen Solaker; Writing by Daren Butler; Editing by Nick Tattersall and Angus MacSwan)