Turkey on Thursday ordered the seizure of the assets of 187 businessmen suspected of links to US-based Islamic preacher Fethullah Gulen, accused by Ankara of masterminding last month's attempted coup, state media reported.

Police launched a vast operation in the country's economic capital Istanbul and other provinces into the alleged Gulen-linked companies -- the biggest crackdown on business since the July 15 failed putsch, the Anadolu news agency reported.

Prosecutors issued arrest warrants for 187 suspects including CEOs of leading companies, with the Istanbul chief prosecutor's office ordering their assets to be seized, the state-run agency added.

Sixty of the suspects were detained, the private Dogan news agency reported.

Local media said around 1,000 police took part in raids at 204 addresses in 18 provinces, which included simultaneous operations at around 100 sites in several districts of Istanbul.

The raids targeted major companies like ready-to-wear retailer Aydinli Group, bakery Gulluoglu Baklava and fashion company Eroglu Holding, Dogan said.

Rizanur Meral, president of the Turkish Confederation of Businessmen and Industrialists (Tuskon), was among the suspects, it added.

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

The wanted suspects are accused of "membership in a terrorist organisation" and "financing the activities" of Gulen, according to Dogan.

In a similar operation on Tuesday, Turkish police raided dozens of companies in Istanbul in search of 120 suspects including CEOs. Around 100 people were detained.

President Recep Tayyip Erdogan has vowed to eradicate businesses, charities and schools linked to Gulen, calling them "terror organisations" and "nests of terror".

Gulen, a reclusive cleric who has lived in self-exile in the United States since 1999, has been repeatedly accused of running a "parallel state" since a corruption scandal embroiling then premier Erdogan and several of his ministers erupted in 2013.

Gulen, 75, once a close ally of Erdogan and the ruling Justice and Development Party (AKP), has strongly denied all of the government's accusations.

Prime Minister Binali Yildirim said Wednesday that 40,029 state employees had been detained in the crackdown on alleged Gulen supporters after last month's attempted coup, of whom 20,335 have been remanded in custody.

More than 5,000 civil servants have been dismissed and almost 80,000 others suspended, he said in an interview with TRT public television.

Ankara wants Washington to extradite Gulen to face trial back home, indicating that any failure to deliver him will severely damage ties.

US Vice President Joe Biden will travel to Ankara next week, the White House said, in the highest ranking visit to Turkey by a Western official since the coup.