In a BBC interview broadcast Tuesday, Obama also restated plans to pursue direct diplomacy with Tehran to encourage it to set aside any ambitions for nuclear weapons it might harbor.
Iran has insisted its nuclear program is aimed at generating electricity. But the U.S. and other Western governments accuse Tehran of seeking atomic weapons.
Obama leaves Tuesday evening on a trip to Egypt and Saudi Arabia aimed at reaching out to the world's 1.5 billion Muslims. He is due to make his speech in Cairo on Thursday.