NEW YORK (Reuters) - Lawyers for an executive at Turkey’s majority state-owned Halkbank who is accused of helping Iran evade U.S. sanctions on Wednesday asked a U.S. federal judge to declare a mistrial as jurors were expected to begin deliberating.

In a motion filed in Manhattan federal court, the lawyers for Mehmet Hakan Atilla said prosecutors had prejudiced the jury by asking their client during cross-examination on Tuesday whether he remembered that a report by a Turkish expert concluded he violated sanctions.

Atilla’s lawyers immediately objected before Atilla could answer, and U.S. District Judge Richard Berman ordered the question stricken from the record. However, Atilla’s lawyers said Wednesday that the damage had been done.

They said jurors should not have been allowed to hear about the Turkish report because its author was not in court, depriving Atilla of his right to confront his accuser. They also said the question “grossly mischaracterized” the report’s conclusion.

“Asking this question in open court had the effect of introducing otherwise inadmissible hearsay and an expert opinion on the ultimate issue for the jury,” they said.

Berman ordered prosecutors to respond to the motion by 5 p.m. (2200 GMT) Wednesday.

Jurors had been expected to begin deliberating Wednesday morning after a three-week trial that has strained diplomatic relations between the United States and Turkey.

At the center of the trial was explosive testimony from Turkish-Iranian gold trader Reza Zarrab, who pleaded guilty to charges of violating sanctions and testified for U.S. prosecutors.

Zarrab testified that Atilla helped design fraudulent transactions of gold and food that allowed Iran to spend its oil and gas revenues abroad, including through U.S. financial institutions, defying U.S. sanctions.

Zarrab also implicated Turkish officials in the scheme, including President Tayyip Erdogan.

Attempts to reach Erdogan’s spokesman for comment on the allegations at the trial have been unsuccessful. Erdogan has publicly dismissed the case as a politically motivated attack on his government.

Atilla, testifying in his own defense at the trial, denied all the charges against him.

Halkbank has denied taking part in any illegal transactions.

Atilla’s lawyers already asked for a mistrial last week after jurors heard testimony from Huseyin Korkmaz, a former Turkish police officer who said he led an investigation that included Atilla and was forced to flee Turkey to escape retaliation. Berman denied that motion.

U.S. prosecutors charged nine people in the criminal case, though only Zarrab, 34, and Atilla, 47, were arrested by U.S. authorities.