(Adds details on Zarrab's guilty plea)
By Brendan Pierson
NEW YORK, Nov 28 (Reuters) - A Turkish-Iranian gold trader has pleaded guilty to conspiring to evade U.S. sanctions against Iran and will testify against a Turkish bank official who is charged with arranging illegal transactions involving American banks, a U.S. prosecutor said on Tuesday.
The trader, Reza Zarrab, will describe a multibillion-dollar international money laundering scheme "from the inside," Assistant U.S. Attorney David Denton said during his opening statement in the New York federal court trial of Mehmet Hakan Atilla, the deputy general manager of Turkey's Halkbank .
Atilla's lawyer, Victor Rocco, attacked Zarrab's credibility in his opening statement, telling jurors that Zarrab was prepared to lie to avoid jail time.
According to court records made public Tuesday, Zarrab pleaded guilty on Oct. 26 to six charges related to the sanctions against Iran.
Zarrab also pleaded guilty to a charge that he bribed a U.S. jail guard to obtain alcohol and a cell phone in 2016, records showed.
The charge does not say how Zarrab used the phone. His lawyer, Benjamin Brafman, declined to comment.
U.S. prosecutors have charged nine people in the case, though only Zarrab and Atilla are known to be in U.S. custody. The other defendants include the former head of Halkbank, Suleyman Aslan, and the former economy minister of Turkey, Zafer Caglayan.
Turkish President Tayyip Erdogan's government has said the case was fabricated for political motives, adding to tensions between Ankara and Washington, NATO allies.
Denton on Tuesday described two schemes intended to help Iran to spend money from global oil sales despite U.S. sanctions. In one, he said, the defendants helped entities in Iran buy gold, which was in turn smuggled to Dubai and sold for U.S. dollars or other currencies.
In the second scheme, Denton said, transactions prohibited by sanctions were disguised as purchases of food, which fell under a humanitarian exemption to the sanctions regime.
Denton said Zarrab's companies carried out transactions, but Atilla, whom he called "an expert on finance and economic sanctions," designed the schemes to make them appear legitimate.
"Zarrab would provide the means, Atilla would provide the method," Denton said.
Denton said Zarrab, Atilla and the other defendants lied to conceal the scheme from U.S. officials.
Denton said the prosecutors' other witnesses would include a former Turkish law enforcement officer who participated in a Turkish investigation into the alleged money laundering scheme, made public in 2013.
Erdogan, then prime minister, called that case an attempted "judicial coup," and it was eventually dropped.
Rocco told the jury that Atilla never took part in a conspiracy.
"Hakan Atilla rarely communicated with Zarrab," he said. "They weren't friends, confidantes or conspirators. They didn't like each other. Reza Zarrab saw Hakan Atilla as a money wrench in his schemes."
Zarrab, Rocco said, bribed other people to further his scheme, including Aslan and Caglayan, but he never bribed Atilla. (Reporting By Brendan Pierson in New York; Editing by Tom Brown)