(Agencies)
Updated: 2008-01-11 09:15

WASHINGTON - The United States sent a formal protest to Iran on Thursday over an incident in which Iranian speedboats aggressively approached US Navy ships in the Strait of Hormuz, the State Department said.

This image released by the US Navy January 8, 2008, and shot January 6 from the bridge of the destroyer USS Hopper, shows 2 small boats, alleged to be Iranian, purportedly racing near the wake of US Navy ships in the Persian Gulf. [Agencies]

A diplomatic protest note was sent via the Swiss ambassador in Tehran who acts as an interlocutor between the US and Iranian governments, which do not have diplomatic ties.

"We have in fact now prepared and given to the Swiss a diplomatic note formally protesting this incident," State Department spokesman Tom Casey told reporters, adding it was delivered on Thursday to the Swiss and would be passed on very quickly to the Iranians.

A State Department official said he did not expect to receive a response from the Iranian government from the note, which made clear US disapproval of the weekend incident, for which the two government have provided differing versions.

US President George W. Bush called the incident a provocative act and warned of "serious consequences" if it happened again, saying all options were on the table.

"We certainly don't want to see the Iranians taking any kinds of provocative actions or steps against our ships or any ships that are transiting what is a primary international waterway," Casey said.

The Strait of Hormuz, the most prominent potential "choke point" for crude oil flows, handles 17 million barrels per day, or two-fifths of globally traded oil.

Iran says it did not threaten US Navy vessels and released its own video on Thursday contradicting a US version of events. Iran dismissed a Pentagon video of the incident as being a fake.

'Lying Eyes'

Asked about the Iranian charge of fabrication, US Defense Secretary Robert Gates said: "I think that the most appropriate answer is actually the one that I heard on television last night from former Secretary of Defense Bill Cohen, who said, 'Are you going to believe me or your lying eyes?'

"I think that aptly characterizes, and appropriately characterizes, the Iranian claim," he told reporters.

Gates said the boats had "behaved in what appeared to be a pretty aggressive manner."

The incident has further heightened tensions between Washington and Tehran, which are already at loggerheads over Iran's nuclear program.

On Wednesday, the United States imposed sanctions on a general in the elite Qods force of Iran's Revolutionary Guard Corps for his alleged role in stoking up violence in Iraq. Iran denies it is fanning the insurgency and says Washington is to blame for the violence.

The United States is also trying to get major powers to agree on the text of a third UN Security Council resolution imposing further sanctions on Iran for its refusal to give up sensitive nuclear work.

Casey conceded there were still "tactical" differences between major powers over the resolution but a senior US official told Reuters he expected there to be an agreement before the end of the month.

So far, Russia and China are reluctant to take more punitive measures, particularly after a US national intelligence estimate released last month said Iran had stopped its nuclear weapons program in 2003.