ISTANBUL A Turkish prosecutor sought a jail sentence of up to 34 years on Thursday for an influential U.S.-based Muslim cleric accused by President Tayyip Erdogan of plotting a coup, the state-run Anadolu Agency said.
In a further sign of authorities stepping up their offensive against Fethullah Gulen, a second prosecutor called for the formal arrest of four businessmen detained in the central Turkish city of Kayseri as part of a police operation targeting the cleric's supporters.
The charges against Gulen include "forming and leading an armed organization", Anadolu said, the latest salvo in Erdogan's two-year battle to wipe out the movement of his former ally.
Authorities have previously issued arrest warrants for Gulen, who has lived in self-imposed exile in Pennsylvania since 1999, and revoked his passport. However, the charges reported on Thursday appear to be the first time that a specific jail sentence has been sought.
In recent weeks the Turkish authorities have shown a renewed zeal for investigations into companies with ties to Gulen's religious movement, which blends conservative, Islamic values with a pro-Western outlook.
The crackdown on Gulen's followers, who also control newspapers critical of the government, comes less than two months before a Nov.1 snap election where the AK Party Erdogan founded is looking to recapture the single-party parliamentary majority it lost in a June poll.
Erdogan's critics see the efforts against Gulen as an attempt to squash opponents ahead of the election.
Thursday's moves are likely to further rattle investors, who have sent the lira currency to a series of record lows on concerns about Turkey's political and economic outlook.
They are also worried about a worsening situation in the mainly Kurdish southeast, where security forces are fighting daily battles with militants of the Kurdistan Workers Party (PKK).
In a series of raids Turkish police have recently targeted Gulen-affiliated conglomerates including mining-to-media group Koza Ipek Holding and Kaynak Holding, which is involved in publishing.
Police detained seven people on Wednesday in Kayseri as part of a probe into a "parallel structure" that Erdogan accuses Gulen of operating in the judiciary and police, local media said. A Kayseri prosecutor on Thursday sought the formal arrest of four businessmen from among the seven.
At the center of the investigation is the city's Meliksah University, whose board of trustees includes businessman Memduh Boydak, one of the seven detained but then later released.
In a statement on its website, the university denied an allegation of "theft by expropriation" over real estate.
"This is an operation to shape perceptions and a legal scandal," it said, adding that a search carried out at the university campus was unlawful and that it would file an official complaint.
Memduh Boydak's group, Kayseri-based Boydak Holding, employs 14,000 people, exports to 140 countries and has annual sales of 6.5 billion lira ($2.2 billion), according to its website.
The Gulen-linked Zaman newspaper said the seven detainees had been asked during their time in custody since Wednesday whether they knew Gulen, had visited him, had any links with the "parallel state structure" or had provided support to it.
Boydak is also a board member of Turkey's leading TUSIAD business association, which issued a statement saying "grave allegations" were constantly unsettling the business world and creating a "gloomy atmosphere".
However, Deputy Prime Minister Cevdet Yilmaz urged business leaders to support the campaign targeting the "parallel structure".
"If there is a parallel structure, there must be a struggle against it. This is a mass struggle and the business world must support it," he told broadcaster NTV on Thursday.
Government officials have accused Gulen's followers of having ties to the PKK. Gulen denies such links, and describes the PKK as a terrorist organization.
A survey published by the pollster Metropoll this week indicated the Gulen movement ranked low among the major problems which Turks believe they face.
According to 42.2 percent of respondents, the biggest problem faced by Turkey was "terrorism/PKK", followed by the economy on 22.4 percent. The Gulen movement ranked 13th with 0.2 percent of participants saying it was the biggest problem.
(Writing by David Dolan and Daren Butler; editing by Gareth Jones)