Iran's Supreme leader Ayatollah Ali Khamenei said Thursday that a speech by President Barack Obama to the Muslim world will not be enough to repair relations.
Khamenei said that efforts by the new American administration to change the "ugly, detested and rough" face of the United States will not be earned solely by "words, speech and slogan."
Khamenei said the Muslim world is instead looking for practical changes to US policies.
Obama is to deliver a speech in Cairo Thursday aimed at establishing a new relationship with the world's 1.5 billion Muslims after years of tense relations under the previous US administration.
Iran and the US have had no diplomatic ties since students in 1979 took over the US embassy in Teheran.