Former Iranian President Mohammad Khatami has called for dialogue between the US and Iran.
Mr Khatami is in the US on a two-week tour
Mr Khatami, on a visit to the US, said relations between the two would improve only through talks, not threats.
His call came as permanent members of the UN Security Council met in Berlin to discuss Iran's nuclear programme.
Mr Khatami's visit has sparked protests from Jewish groups, Iranian exiles and some politicians who regard Tehran as a threat to the US.
During a speech on Thursday in Washington, the former leader called for greater understanding between East and West.
He said talks between Washington and Tehran would "open the path to a better tomorrow and to rescue life from the claws of warmongers and violence-seekers and ostentatious leaders".
In previous speeches during his two-week US tour he defended Iran's nuclear programme, which he insisted was peaceful.
He said Tehran would consider suspending the programme if Western powers would talk without conditions.
Mr Khatami - who was in power between 1997 and 2005 - was granted a visa by the US government, but is not meeting any officials during his visit.
Later, he will speak at Harvard University and attend the United Nations in New York.