His comments followed three hours of talks with European Union foreign policy chief Javier Solana in the Austrian capital.
The talks are aimed at preventing a further escalation in a three-year showdown over what the United States suspects is a covert Iranian nuclear weapons program.
The US wants a United Nations Security Council resolution imposing sanctions against Iran as early as next weeks. Iran is refusing to suspend uranium enrichment, despite being offered trade and other benefits in return.
Iran says its nuclear program is aimed at producing nuclear energy and not nuclear weapons.