Obama says that the "diplomatic path with Iran must be tested"
President Obama told the United Nations General Assembly, however, that Rouhani's “conciliatory words will have to be matched by actions that are transparent and verifiable.”
The West has long suspected that Iran is seeking a nuclear weapon. Tehran has consistently denied the charge.
It's still unclear if President Obama will meet with Rouhani while at the United Nations. The leaders of the two countries haven't had face-to-face contact in more than 30 years.
U.S. officials say no meeting is planned, although they haven't ruled one out.
Iranian Foreign Ministry said a meeting between Iran's top diplomats and world powers at the United Nations this week will start a “new era” in efforts to end a dispute with the West over Tehran's disputed nuclear program.
It did not hint at any concessions that could draw further criticism from hardline groups who have voiced their concerns over signs of a possible rapprochement with the United States.
The European Union said on Monday that Iranian Foreign Minister Javad Zarif would meet the representatives of Britain, France, China, Russia, the United States and Germany to discuss the Iranian nuclear program.