U.S. Navy Buildup Came After Iran Moves

Vice Admiral Patrick Walsh, commander of U.S. Naval Forces Central Command and 5th Fleet, speaks to journalists Monday, Feb. 19, 2007, at the U.S. Navy base in Manama, Bahrain. Walsh says the United States, which sent a second aircraft carrier to the Persian Gulf for the first time since the 2003 Iraq invasion, is keeping a close eye on Iranian military exercises. (AP Photo/Hasan Jamali) (Hasan Jamali - AP)

The Straits of Hormuz are 34 miles across, but its shipping lanes are only about six miles wide.

Walsh said it was doubtful that Iran could physically block the entire six-mile lanes with mines _ but hitting only a few vessels with missiles and mines would "terrorize" shipping and have the same effect.

"It's more the threat of mines than the threat of closing the straits. That would have dramatic effects on markets around the world," he said.

Walsh said his biggest worry was that Iran would underestimate U.S. resolve to protect its interests in the world's richest oil region. He said the tone of Iranian leaders could make their commanders on the ground more reckless. "It's a mix and a formulation where you can have misunderstanding," he said.

Asked whether the U.S. Navy would launch an attack on Iran if Iranian involvement were confirmed in a deadly incident in Iraq, Walsh said he was unable to discuss the Navy's rules of engagement. But he added, "There are events on land that can spill over onto the sea."

At the same time, Walsh said he understood that U.S.-allied Gulf nations feared that any U.S.-Iranian military conflict could bring attacks on their soil.

Walsh said he was aware that a University of Maryland/Zogby International poll of Arab public opinion this month showed residents of the United Arab Emirates, Saudi Arabia and other allies believe Iran is far less a threat than the U.S. and Israel.

"I'm trying to talk to those in the region, to give them assurances that the reason we're here is to stand by them," he said.