Turkish president Tayyip Erdogan, who was accused cleric Fethullah Gulen of infecting Turkey with 'nests of terrorism'

Turkisk president Tayyip Erdogan has vowed to cut off the business revenues of a US-based cleric he blames for masterminding a failed military coup - calling his companies and charities 'nests of terrorism'.

The Turkish leader has blamed Fethullah Gulen of plotting the uprising, which rogue soldiers commandeer fighter jets, helicopters and tanks and capture bridges in a bid to seize power.

However, Gulen who lives in exile in Pennsylvania has denied any involvement in the coup and has suggest Erdogan may have staged it himself to increase his power.

But in a new speech that was broadcast live from the presidential palace in Ankara, Erdogan pledged to show no mercy in a crackdown on the cleric's interests.

He accused Gulen of harnessing his extensive network of schools, charities and businesses, built up in Turkey and abroad over decades, to infiltrate state institutions and build a 'parallel structure' that aimed to take over the country.

More than 60,000 people in the military, judiciary, civil service and education have been detained, suspended or placed under investigation for alleged links to Gulen's 'Hizmet' (Service) movement since the July 15 coup attempt.

Erdogan told business leaders: 'They have nothing to do with a religious community, they are a fully-fledged terrorist organisation ... This cancer is different, this virus has spread everywhere.

'The business world is where they are the strongest. We will cut off all business links, all revenues of Gulen-linked business. We are not going to show anyone any mercy.'

The Turkish authorities had already seized a bank, taken over or closed several media companies, and detained businessmen on allegations of funding the cleric's movement ahead of the failed coup attempt.

The Turkish leader has blamed Fethullah Gulen, pictured, of plotting the uprising, which rogue soldiers commandeer fighter jets, helicopters and tanks and capture bridges in a bid to seize power

The news comes as the Austrian chancellor said there were signs that Turkey is heading toward a dictatorship and questioned the sense of continuing negotiations with it over EU membership.

Christian Kern added it may be time to push the 'reset button' on the talks, adding he wants 'critical discussions' of the topic at next month's EU summit.

He said 'there is no realistic perspective for membership' for Turkey. Instead, the Austrian leader calls for a 'new approach' based on the need for close economic ties between the EU and Ankara.