Turkey has seized the assets of a gold trader whose testimony in a corruption case in New York has implicated President Erdogan in a scheme to help Iran evade US sanctions.
Having pleaded guilty himself, Reza Zarrab is cooperating with US prosecutors in the trial of a Turkish bank executive who denies helping Iran launder money.
The Turkish government has slammed the case as politically-inspired.
Istanbul resident Mehmet Bozkurt seemed to agree.
"I don't believe America's interventions are based on the law," he said.
"It is an economic sanction, a way to clamp down on Turkey. They want our economy to collapse. They don't want Turkey to progress."
The case has aggravated tension between Turkey and the US, allies in NATO.
Fellow Istanbul dweller Cafer Damsa condemned Zarrab - a dual Turkish-Iranian national - saying that what he is doing is detrimental to Turkey.
"I think this is an American game, a conspiracy... I see him as a spy, a spy for America," he said.
US prosecutors charge that the man on trial, Mehmet Hakan Atilla, an executive of Turkey's state-owned Halkbank, helped Iran launder money. Halkbank, like Atilla, has said it is not guilty of the charges.
In his testimony, Zarrab also said that Turkish officials had authorised two Turkish banks, Ziraat Bank and VakifBank, to move funds for Iran.
Both Ziraat and VakifBank have denied taking part in any such scheme.
Zarrab has said that Erdogan, when he was prime minister, and ex-Treasury Minister Ali Babacan signed off on a transaction in the alleged money laundering conspiracy.
Despite the denials from the banks mentioned in the case, economic fall-out is feared if US authorities impose fines.
With Zarrab's testimony also implicating several former Turkish ministers, some believe the whole episode will be used by the Erdogan government to rally nationalist support.