Greek Prime Minister George Papandreou says he raised the matter of two American hikers jailed on spying charges in Iran during a meeting with Iranian President Mahmoud Ahmadinejad.
No details of the talks were disclosed, but U.S. Vice President Joe Biden says he is grateful for Mr. Papandreou's efforts.
The Greek prime minister and the Iranian president met in New York, where both men are attending the U.N. Millennium Development Goals summit.
Iran detained three American hikers who accidentally crossed into Iranian territory from Iraq in July of last year. Last week the one woman in the group was freed, but Mr. Ahmadinejad said he was unable to release her two companions.
The three detainees all deny taking any action that could be interpreted as spying. Sarah Shourd, who arrived back in the United States Sunday, said if they crossed Iran's border it was purely by accident, and she appealed for the release of the two men still in Tehran's Evin Prison - her fiance, who lived with her in Damascus, and a visiting American friend who was touring the Kurdish portion of Iraq with them last year.
Mr. Biden, who met with Mr. Papandreou in Washington Tuesday, said he complimented the Greek leader for what he described as an "incredible job" of managing Greece's financial crisis and putting the country back on the right track.
Mr. Papandreou said he and the U.S. vice president also discussed the Middle East peace process. He also called on Turkey to move forward toward a settlement on Cyprus and the eventual withdrawal of Turkish forces from the island.
Some information for this report was provided by AP, AFP and Reuters.