A top adviser to Barack Obama said the president will not meet with Iranian President Mahmoud Ahmadinejad at the United Nations next week.
Susan Rice, the US ambassador to the United Nations, said, "I don't expect that they will have a direct engagement."
Obama will be in New York from Monday to Wednesday for the gathering of the 192-member UN General Assembly.
Rice spoke on Friday, after Ahmadinejad lashed out at Israel and the West and again questioned whether the Holocaust happened.
Rice called those comments "hateful." White House spokesman Robert Gibbs told reporters: "Obviously we condemn what he said."
The US accuses Iran of running an illicit nuclear weapons program. Iran denies that.