US Navy patrols Persian Gulf
US Navy patrols Persian GulfIsrael news photo: US Navy

Britain is warning Iran it may resort to military action if Tehran attempts to close the Strait of Hormuz, a major shipping lane for much of the world's oil supplies.

Last month, Iran said it was holding a military drill that would include exercises on how to close of the Strait of Hormuz, the waterway through which some 40 percent of the world's oil is shipped to markets in the West.

The Islamic Republic followed the threat with another earlier this week by Iranian army chief Ayatollah Salehi, warning USS carrier John C Stennis not to return to the Persian Gulf after having left the area through the Straits of Hormuz in a "pre-planned, routine operation."

The U.S. responded to the Iranian threat with a calm statement read by Pentagon spokesman George Little warning Iran, "The deployment of U.S. military assets in the Persian Gulf region will continue as it has for decades."

Likewise, a U.S. Navy spokesman told reporters in an emailed statement Tuesday, "The United States is committed to ensuring the safe flow of maritime traffic in waterways critical to global commerce."

"Our joint naval presence in the Arabian Gulf, something our regional partners appreciate, is key to keeping the Straits of Hormuz open for international trade," UK Defense Secretary Philip Hammond is expected to say in the text of a speech released to the media ahead of his appearance in Washington later Thursday.

Any attempt by Iran to block the waterway in retaliation for sanctions against its oil exports would be "illegal and unsuccessful," Hammond is expected to warn the Islamic Republic, "and the Royal Navy stands ready to join any action to keep the Strait open.

"Disruption to the flow of oil through the Straits of Hormuz would threaten regional and global economic growth...  It is in all our interests that the arteries of global trade are kept free, open and running."