Barrack's defense revealed the plans in a letter to U.S. District Judge Brian Cogan in which it requested that Tillerson take the stand on Monday. The defense said prosecutors had confirmed that they would be calling Tillerson, but informed the defense he would be unavailable after Oct. 4 due to "personal plans."

Having Tillerson take the stand on Monday would ensure that the defense has enough time to cross-examine him, Barrack's lawyers said.

Tillerson could not immediately be reached for comment.

A spokesman for the U.S. Attorney's office in Brooklyn, where Barrack is being tried, declined to comment.

Barrack has pleaded not guilty. His lawyers have said his interactions with Emirati officials were part of his role running private equity firm Colony Capital, now known as DigitalBridge Group Inc.

Tillerson, the former chief executive of ExxonMobil, served as Trump's secretary of state for slightly more than a year from 2017 to 2018.

(Reporting by Luc Cohen in New York; Editing by Richard Chang)

By Luc Cohen