Hassan Rouhani also said the recent elections that propelled him to the Iranian presidency created a "new environment" that could pave the way for better relations with the West.
Rouhani said at a news conference in New York that he did not meet with Obama on the sidelines of the UN General Assembly this week because there was not enough time to plan such a high-stakes meeting.
But he says Iran emerged hopeful from a lower-level meeting with the US and its international partners aimed at restarting talks to settle their nuclear standoff.