Iran's supreme leader says oil flows in the region will be disrupted if the United States makes what he calls a "wrong move" towards the Islamic Republic.
But Ayatollah Ali Khamenei did not specify how supplies would be affected when he made the threat during a speech on Sunday broadcast live on state radio.
U.S. Secretary of State Condoleezza Rice says the international community should not place much emphasis on the threat. Rice says Iran depends on oil revenues and a disruption in oil supply would be a serious problem for Iran.
Rice, speaking on an American television network Fox News Sunday, added that Iran should get a Western incentive package to stop enriching uranium in the coming days. She says the international community, not just the United States, is demanding Iran suspend the sensitive nuclear process.
European Union foreign policy chief Javier Solana is expected to arrive in Tehran this week to present the proposal.
Western countries suspect Tehran is enriching uranium to make nuclear weapons. Iran insists its nuclear program is for peaceful purposes.