Turkey's foreign minister blamed the alleged mastermind of the failed 2016 coup for a legal case in the United States against Turkish-Iranian businessman Reza Zarrab that has angered Ankara.

Foreign Minister Mevlut Cavusoglu said the group of the US-based Islamic preacher Fethullah Gulen -- who denies being behind the coup -- had succeeded in infiltrating the US justice system.

Zarrab is due to go on trial alongside Mehmet Hakan Atilla, the deputy chief executive of Turkish lender Halkbank, on November 27 in New York on charges of violating sanctions against Iran, a case some commentators see as potentially damaging for Ankara.

"This case is very much FETO-motivated," Cavusoglu told reporters. "This is for sure.

"And all those indictments and files that they have fabricated here, they were taken back to the United States."

Ankara accuses Gulen of running a group called the Fethullah Terror Organisation (FETO). Gulen's supporters ridicule the term, saying he runs a peaceful organisation called Hizmet (Service).

The arrest of Zarrab last year intrigued opponents of the government in Turkey, where Zarrab had been linked to a 2013 corruption scandal that had ensnared the elite at a time when Turkish President Recep Tayyip Erdogan was prime minister.

All suspects arrested in the probe were subsequently released. Zarrab had spent 70 days in custody in Turkey over the scandal, which Erdogan denounced as a plot by Gulen to bring down his government.

NBC in the United States reported Thursday that Zarrab was now cooperating with prosecutors, raising the prospect that he may be seeking a plea bargain deal and give evidence for the prosecution.

Neither Zarrab, 34, nor his lawyer attended a court hearing in Manhattan on Thursday to discuss the case ahead of the trial

Turkey has in the last days expressed concern over his whereabouts, even sending a diplomatic note to Washington.

But Cavusoglu said Ankara had nothing to fear even if Zarrab was cooperating.

"Why should I be concerned? We have a saying in Turkey 'if I did not drink bad milk, why should I worry about my stomach?'." he said.

He added: "Of course if something is fabricated we also have something to say."

He said the former top prosecutor for Manhattan Preet Bharara, who brought the charges, is "very close to FETO and he is not hiding this." Bharara has in the past ridiculed such accusations.

President Donald Trump's former national security advisor Michael Flynn is reportedly being investigated by special prosecutor Robert Mueller for alleged talks with Turkey on deporting Zarrab and Gulen in exchange for money.

Turkey and Flynn's lawyers have denied any such negotiations.

Source: AFP