Tehran: The latest in a series of Iranian threats to block the vital Strait of Hormuz triggered a sharp response from the US Navy, although there appeared to be little chance that Tehran would make good on its warnings.

Despite threats to close the narrow waterway if Western nations tighten sanctions on Iran by imposing an oil embargo, the Islamic Republic needs the strait at least as much as its adversaries do, Iranian and foreign analysts said.

Iran, which feels threatened by the presence of US bases and warships in the region, has warned for years that it would choke off the Strait of Hormuz in case of war or economic sanctions.

The passage at the entrance to the Arabian Gulf hosts a daily caravan of tankers that transport roughly a third of the world's oil shipments.

And Iran itself — which has enjoyed record oil profits over the past five years but is faced with a dwindling number of oil customers — relies on the Hormuz Strait as the departure gate for its biggest client: China.

Telling assessment

"We would be committing economical suicide by closing off the Hormuz Strait," said an Iranian Oil Ministry official who requested anonymity because of the sensitivity of the subject. "Oil money is our only income, so we would be spectacularly shooting ourselves in the foot by doing that."

Ahmad Bakhshayesh Ardestani, a political scientist running for parliament from the camp of clerics and commanders opposing Ahmadinejad, said it is "good politics" for Iran to respond to US threats with threats of its own.

"But our threat will not be realised," Ardestani said. "We are just responding to the US, nothing more."

The European Union, encouraged by the United States, is expected to decide in January whether to boycott Iranian crude. And countries such as Japan and South Korea are under increasing US pressure to stop buying oil from Iran.

A closure could prompt a spike in oil prices, analysts said, further damaging the troubled world economy.

In addition to the threats, Iran has started a 10-day naval exercise to demonstrate what it calls ‘asymmetrical warfare', a military doctrine aimed at defeating US aircraft carriers in a potential Gulf conflict by using swarms of rocket-mounted speedboats and a barrage of missiles.

US response

In Bahrain, home of the US Navy's 5th Fleet, a spokeswoman for the fleet said no country would be allowed to block the strategically crucial strait. The Navy is "ready to counter malevolent actions," Lt. Rebecca Rebarich added. "Anyone who threatens to disrupt freedom of navigation in an international strait is clearly outside the community of nations," she said.

A State Department spokesman downplayed the warnings as "more rhetoric" from the Iranians. "As the 5th Fleet has said, and I believe other governments have also said, it's absolutely critical that there be freedom of navigation in these international waters," Mark Toner, said on Wednesday.

Strategic advantage

Oil producers have not been sitting idle in the face of decades of Iranian threats to shut off the only regional oil transportation corridor.

The UAE has nearly finished a 2.5 million-barrel-a-day pipeline circumventing the Arabian Gulf. UAE officials say the Abu Dhabi Crude Oil Pipeline Project is a "strategic pass", circumventing the Hormuz Strait in case Iran closes the chokepoint.

Iranian officials insist that the UAE pipeline and others that are being constructed in the region will not lessen the strategic importance of the Hormuz Strait. But they have raised the issue repeatedly, which analysts say is a sign that they are, in fact, nervous about it.

— Washington Post