A U.S. judge denied bail on Thursday to the Iranian-Turkish businessman Reza Zarrab on charges he conspired to violate U.S. sanctions against Iran, rejecting the defendant's proposal that he hire his own guards to keep him in custody.U.S. District Judge Richard Berman in Manhattan said federal prosecutors showed it was more likely than not that the trader, Reza Zarrab, posed a flight risk if freed from federal custody and that no conditions would reasonably assure his appearance at trial. He has been in custody since March.The judge said the Iranian-born Zarrab, a dual national of Iran and Turkey, had no ties to the United States, has significant financial resources, and has strong ties to other countries that would not extradite him if requested.Those factors "provide Mr. Zarrab with the incentive and the wherewithal to flee and render him a flight risk," Berman said.Benjamin Brafman, a lawyer for Zarrab, did not immediately respond to requests for comment.Zarrab had sought to be released on $50 million bond, and held in a 15th-floor Manhattan apartment under 24-hour watch by armed guards at his own expense.Zarrab, 33, was arrested in Miami on March 19, on charges contained in a federal indictment in Manhattan against him and two Iranian citizens, Kamelia Jamshidy, 29, and Hossein Najafzadeh, 65.Zarrab, Jamshidy and Najafzadeh are being accused of engaging in hundreds of millions of dollars-worth of transactions on behalf of the government of Iran and other Iranian entities, which were barred by U.S. sanctions, laundering the proceeds of those illegal transactions and defrauding several financial institutions by concealing the true nature of these transactions.

Several companies based in Turkey are also being accused in the indictment of facilitating the transactions.