President Recep Tayyip Erdogan on Tuesday launched his most bitter attack yet on Turkey’s Western allies over the July 15 attempted putsch.

President Recep Tayyip Erdogan on Tuesday launched his most bitter attack yet on Turkey's Western allies over the July 15 attempted putsch, accusing them of supporting both "terror" and the coup plotters who tried to unseat him.

Erdogan, who blames the plot on the US-based preacher Fethullah Gulen, also described the coup as a "scenario written from outside" in an allusion to foreign involvement.

Turkey meanwhile issued arrest warrants for about 100 staff, including doctors, at Ankara's main military hospital, and even fired football referees in a new phase of the crackdown after the failed coup that has seen some 18,000 detained and caused international consternation.

"Unfortunately, the West is supporting terror and standing by the coup plotters," said Erdogan in a typically combative speech at his presidential palace, denouncing "those who we imagined to be friends".

Erdogan lashed out at Germany's judicial authorities for not allowing him to address via video conference a weekend rally in Cologne in his support.

"Bravo! The courts in Germany work very fast!" Erdogan said with heavy irony.

He accused Germany of allowing leaders from the outlawed Kurdistan Workers Party (PKK) to address previous events via video conference.

The president, who had previously alluded to foreign states' involvement, gave his strongest indication yet that external powers could have played a role.

"This coup was not just an event planned from the inside. The actors inside acted out a scenario for a coup written from the outside," Erdogan said.

Turning directly on Washington over its hosting of Gulen, he asked: "How can it be, when we are strategic partners... you keep on hiding and sheltering him?"

Already strained ties between NATO allies Turkey and the United States have been aggravated by the failed putsch, with some government ministers even alleging Washington could have had a hand in the plot, which US officials firmly reject.

Erdogan also rounded on the European Union, saying it had "not yet lived up to its promises" in a deal on reducing the flow of migrants to Europe.