Twenty-one journalists also appeared in an Istanbul court after being rounded up in the sweeping purge, which has seen almost 16,000 people detained since the failed July 15 putsch.
Turkish authorities blame Gulen for the rebellion, which aimed to unseat President Recep Tayyip Erdogan, and they are now seeking to erase the reclusive cleric's influence from all aspects of Turkish life.
But the scale of the crackdown has sparked international alarm, with the EU enlargement commissioner implicitly warning the bloc would freeze Turkey's accession talks if it violated the rule of law.
"And if there is even the slightest doubt that the (treatment) is improper, then the consequences will be inevitable," he told German daily Sueddeutsche Zeitung.
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Following a shake-up of the military on Thursday after nearly half of its 358 generals were sacked, the top brass of the reshuffled armed forces met Erdogan at his presidential palace in Ankara.
Ninety-nine colonels have been promoted to generals and admirals, although Chief of staff General Hulusi Akar -- who was held hostage during the coup attempt -- stayed in his post along with the heads of the navy, land and air forces.
"When we weed them (pro-Gulenist elements) out, our army will first of all be more dynamic, cleaner and more effective," Foreign Minister Mevlut Cavusoglu said, dismissing concerns that the forces would be weakened.
Meanwhile the probe into coup plotters shifted focus to the financing of Gulen's activities in Turkey, with what appeared to be the first major arrests targeting the business world.
Security forces in the central city of Kayseri detained the chairman of the family-owned Boydak Holding company, Mustafa Boydak, and two other top executives, state-run Anadolu news agency said.