Iran has threatened to block the shipment of oil through the Strait of Hormuz if Western governments try to impose sanctions on its petroleum exports in response to the country's nuclear program.

Iran's navy chief told state television Wednesday that it would be easy to close off the strait, but that such action is not necessary at this time.

His comments come a day after Vice President Mohammad Reza Rahimi said that if Iranian oil is banned, “then not a drop of oil will pass through the Strait of Hormuz.”

Rahimi was quoted by the official Iranian news agency IRNA as saying Iran does not want hostilities but that Westerners are not willing to give up “their plots.”

The blunt warning came as Iran's naval forces continued a 10-day exercise in the Strait and nearby waters that began Saturday.

In Washington, U.S. State Department spokesman Mark Toner dismissed the threat as “bluster.” He called the comments “another attempt to distract attention from [Iran's] continued noncompliance with international nuclear obligations.”

Iran contends its uranium enrichment program is for civilian purposes, but a United Nations report issued last month said Tehran appears to be secretly working on designing an atomic weapon and missile delivery system.

European Union ministers have said that a decision on further economic sanctions – including the question of whether to boycott Iranian oil – would be made in the coming weeks. The vast majority of Iran's foreign revenue comes from oil exports.

More than one-third of the world's tanker-borne oil supply passes through the Strait of Hormuz.