Turkish police launched a vast operation Thursday targeting businesses suspected of financing US-based Muslim preacher Fethullah Gulen, accused by Ankara of masterminding last month’s attempted coup, media reported.

Prosecutors issued arrest warrants for 187 suspects including CEOs as part of the operation in the country’s economic capital of Istanbul and other provinces, CNN-Turk reported.

It said around 1,000 police took part in the operation in 204 addresses in 18 provinces, which included simultaneous raids in about 100 sites in several districts of Istanbul.

Rizanur Meral, the president of the Turkish Confederation of Businessmen and Industrialists (Tuskon), was among the suspects wanted by authorities, the private Dogan news agency reported.

Founded in 2005, Tuskon has 55,000 members and is accused by the government of financing pro-Gulen activities.

The suspects are accused of “membership in a terrorist organization’ and “financing the activities” of Gulen, blamed by authorities for orchestrating the July 15 putsch, according to Dogan.

Prime Minister Binali Yildirim said late Wednesday that 40,029 state employees have been detained in the crackdown on alleged Gulen supporters in the wake of the failed July 15 coup, of whom 20,335 have been remanded in custody.