ISTANBUL (Reuters) - Turkey is to seize the assets of a Turkish-Iranian gold trader who is a key witness in the trial of a Turkish bank executive in the United States over violations of Iran sanctions, the state-run Anadolu news agency said on Friday. Turkish Prime Minister Binali Yildirim said on Friday he hoped gold trader Reza Zarrab would  turn back from his mistake  in cooperating with U.S. prosecutors, reiterating Ankara s view that the criminal trial in New York was aimed at putting pressure on Turkey and its economy. The Istanbul prosecutor s office decided to seize the assets of Zarrab and those of his acquaintances as part of an investigation against him, Anadolu said. The prosecutor s office was not immediately available for comment. 