U.S.: Iran ' saber-rattling ' over strait

• The U.S. will do "what we must" to keep the strait open, official says
• Iran says it will do what it sees fit for its defense
• Europe wants tougher sanctions on Iran over its nuclear program

(CNN) -- The Obama administration said Iran has been "saber-rattling" over its threat to block the strategically important Strait of Hormuz and renewed its vow Thursday to keep the corridor open.

But the Islamic republic's military underscored its intention Thursday to undertake whatever military maneuvers it sees fit on the waterway.

This is the latest in the recent war of words between the United States and Iran over the strait.

It started when Tehran's vice president this week warned that the country could block the strait if sanctions are imposed on its exports of crude oil. The U.S. Fifth Fleet based in Bahrain countered that "any disruption will not be tolerated."

The shipping channel leads in and out of the Persian Gulf between Iran on one coast and Oman and the United Arab Emirates on the other. It is strategically important because tankers carrying oil travel through it.

An Obama administration official, speaking on background because of the sensitivity of the issue, said the government has been "committed to Gulf security for decades and it should come as no surprise to anyone that we'll do what we must to ensure the strait remains open."

Iranian Brig. Gen. Hossein Salami, deputy commander of Iran's Islamic Revolution Guards Corps, said his country "asks for no other country's permission for the implementation of its defense strategies," state-run Press TV reported on Thursday.

On Wednesday, Iran's Navy Commander Rear Admiral Habibollah Sayyari said, "Iran has total control over the strategic water way," adding that, "Closing the Strait of Hormuz is very easy for Iranian naval forces." The vice president, Mohammad Reza Rahimi, issued his threat on Tuesday.

"Iran has repeatedly warned that in the event of a military attack on the country, it will not hesitate in taking all necessary measures to protect its sovereignty one of which would be to close the strategic oil passage," Press TV said in its report.

The administration official stressed that "the saber-rattling is really all on the Iranian side."

Iran has been holding a 10-day military exercise in an area from the eastern part of the strait out into the Arabian Sea. Western diplomats describe the maneuvers as further evidence of Iran's volatile behavior.

France, Britain and Germany have proposed sanctions to punish Iran's lack of cooperation on its nuclear program. Western powers believe Iran is intent on building nuclear weapons, but Iran says its nuclear program is for peaceful purposes.

Physically closing the strait would require means that likely are not available to Iran, said Professor Jean-Paul Rodrigue of Hofstra University.

"At best, Iran can posture and potentially disrupt traffic for a short duration," said Rodrigue, who specializes in global trade and maritime transportation issues.

Rodrigue told CNN that any move by Iran to close the strait would be "suicidal" to the current regime.

In 2009, 15 million barrels of oil passed through the strait every day, according to the U.S. Energy Information Administration.

"Keep in mind that countries such as China and Japan are more dependent on Persian Gulf oil than the United States," the professor said.

About 18% of U.S. net petroleum imports come from the Persian Gulf region, while Canada provides 25%, according to Rodrigue.

The scholar, who has written extensively about oil "chokepoints," said there are no other means to move large quantities of oil over long distance than by maritime transportation.

"It is thus an international issue where the United States, for strategic and historical reasons, is spearheading its security," Rodrigue said.

CNN's Phil Gast and Jill Dougherty contributed to this report.