Iran says it plans to review the eight-year prison sentence given to the Iranian-American journalist, Roxana Saberi.
Ms Saberi was convicted last month of spying for the United States.
The Iranian authorities say they have firm evidence that Ms Saberi was spying, but that evidence has never been published.
Many journalists in Iran believe that her arrest and conviction were really meant to send a warning to other reporters about their conduct in the run up to presidential elections in Iran in June.
Visiting Japanese Foreign Minister Hirofumi Nakasone said his government was following the case of Ms Saberi, whose mother is Japanese, with "concern".
Ms Saberi, who according to her father is on hunger strike, was jailed on April 18 to eight years after she was found guilty of espionage.
Her lawyer has appealed the verdict.
"The has been a review request for her and this review will be implemented based on justice and human and Islamic kindness," Iran's Foreign Minister Manoucher Mottaki said in a joint press conference with Mr Nakasone.
Iranian judiciary officials have said Saberi is in good health and that she is not on hunger strike.
Her father Reza Saberi has described her condition as "frail and weak".
The case could complicate Washington's efforts towards reconciliation with the Islamic Republic after three decades of mutual mistrust.