JERUSALEM (CNN) -- The war of words between United States and Tehran continued Wednesday, with President Bush repeating his assertion that Iran is "a threat to world peace."

President Bush and Israeli Prime Minister Ehud Olmert at the airport in Tel Aviv on Wednesday.

The two countries have been trading accusations since a weekend confrontation involving Iranian boats and U.S. Navy warships in the Strait of Hormuz. The United States claims Iranian vessels deliberately sped toward its warships despite warnings to stay away.

Bush's criticism of Iran came Wednesday during a news conference with Israeli Prime Minister Ehud Olmert in Jerusalem. Bush is in the region to encourage the peace process between Israel and the Palestinians.

Bush called the incident "a very dangerous gesture" by Iran and warned the Islamic republic against any escalation.

"We have made it very clear, and they know our position, and that is: There will be serious consequences if they attack our ships, pure and simple."

"My advice to them is: Don't do it."

Earlier in the day, National Security Adviser Stephen Hadley said the Sunday incident in the Strait of Hormuz almost triggered an exchange of fire -- and if it happens again there may be a battle.

The Pentagon released dramatic video of Sunday's encounter, which occurred in the narrow channel critical to the shipment of oil from the Persian Gulf. Iran's navy said the video was faked, according to state-run media.

"It's the kind of incident that can provoke exchange of fire," Hadley said. "And we think the Iranians need to be on notice that they are fishing in troubled waters here."

Hadley, speaking to reporters aboard Air Force One as Bush headed to Israel, said, "It almost involved an exchange of fire between our forces and Iranian forces," but he stopped short of saying whether the U.S. Navy would have fired the first shots.

"This is not -- this is a provocative act, not a smart thing to do, and they're going to have to take responsibility for the consequences if they do it again," Hadley said.

Vice Adm. Kevin Cosgriff, commander of the Bahrain-based U.S. 5th Fleet, said the U.S. ships received a "threatening" radio transmission indicating the boats were closing in on the U.S. ships and that the American vessels would "explode." Watch as the confrontation unfolds »

No shots were fired, and no one was hurt in the incident, which lasted about 20 minutes, the Defense Department said.

It began as the USS Port Royal, USS Hopper and USS Ingraham were traveling in formation after having finished a routine transit through the strait, the Navy said.

Five boats, suspected to be from the Islamic Republic of Iran Revolutionary Guard Navy, "maneuvered aggressively in close proximity of the Hopper," the Navy said in a posting on its Web site.

On Tuesday, the Pentagon released a four-minute, 20-second videotape shot from the bridge of the USS Hopper showing five fast boats racing back and forth near the convoy.

An unidentified Navy crew member says over the radio: "This is coalition warship. I am engaged in transit passage in accordance with international law. I intend no harm. Over."

The boats continued to race through the water even as the U.S. warship repeatedly sounded its horns.

"I am coming to you," a deep, thickly accented voice says in English over the radio.

To that, an unidentified sailor aboard the Hopper, speaking into a radio, asks the boats to identify themselves and steer clear.

"Inbound small craft: You are approaching a coalition warship operating in international waters. Your identity is not known; your intentions are unclear," he says.

"You may be subject to defensive measures. Request that you establish communications now or alter your course immediately to remain clear."

Immediately afterward, an accented voice says, "You will explode in a few minutes."

It was not clear, however, that the voice was coming from any of the boats, said Cmdr. Lydia Robertson, the 5th Fleet spokeswoman in Bahrain. It could have come from another ship in the area or from shore, she said.

"We don't have a direct connection, but it's not necessarily a disconnect," she said.

Nor was it clear that the boats indeed belonged to the Revolutionary Guard Navy, she acknowledged. "We believe they are," she said, adding that "at least one had an Iranian flag."

But Chris Madden, the Navy's visual news director, said no Iranian flags were visible in the video.

Robertson said estimates of the boats' nearest proximity to the warships range from 200 to 500 yards. She called the fast boats' actions "unsafe, unnecessary and unprofessional."

Though the video does not show it, at least one of the boats dropped about five or six objects that looked like boxes into the water, where they floated, Robertson said.

The U.S. naval commanders did not pick them up "because they did not know what they were," she said.

Iran's state-run Press TV quoted a spokesman for Iran's Revolutionary Guard Navy as saying Wednesday that the video "had been compiled using file pictures and the audio had been fabricated."

An Iranian Foreign Ministry spokesman downplayed the incident, calling it "normal," state-run news agency IRNA reported. "The case ... was similar to the past ones and it was a regular and natural issue," Mohammad-Ali Hosseini said, according to the news agency. E-mail to a friend

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