TEHRAN: Iran threatened on Tuesday to stop the flow of oil through the Strait of Hormuz if foreign sanctions were imposed on its crude exports over its nuclear ambitions, a move that could trigger military conflict with economies dependent on Gulf oil.

"If they (the West) impose sanctions on Iran's oil exports, then even one drop of oil cannot flow from the Strait of Hormuz," the official Iranian news agency IRNA quoted Iran's First Vice President Mohammad Reza Rahimi as saying.

Rahimi's remarks coincided with a 10-day Iranian naval exercise in the Strait and nearby waters, a show of military force that began on Saturday.

"Our enemies will give up on their plots against Iran only if we give them a firm and strong lesson," Rahimi said.

The U.S. State Department said it saw "an element of bluster" in the threat but underscored that the United States would support the free flow of oil.

"It's another attempt to distract attention away from the real issue, which is their continued non-compliance with their international nuclear obligations," spokesman Mark Toner said.

Western tensions with Iran have increased since a November 8 report by the UN nuclear watchdog saying Tehran appears to have worked on designing an atomic bomb and may still be pursuing research to that end. Iran strongly denies this and says it is developing nuclear energy for peaceful purposes.

Iran has defiantly expanded nuclear activity despite four rounds of UN sanctions meted out since 2006 over its refusal to suspend sensitive uranium enrichment and open up to U.N. nuclear inspectors and investigators