Secretary of State Hillary Clinton says journalist Roxana Saberi is innocent of the charges against her and should be freed immediately.
Saberi was convicted of spying on Iran, and sentenced to eight years in prison.
Saberi is an American who's lived in Iran for the past six years, working as a freelance reporter for the BBC and National Public Radio. Her father says she's writing a book on Iranian culture.
Iranian president Mahmoud Ahmadinejad told the prosecutor Saberi should be given a full defense.
President Obama says he is "gravely concerned" for her well-being.