A U.S. aircraft carrier strike group sailed through the Strait of Hormuz on Tuesday shadowed by Iranian patrol boats and aircraft.
The maneuvers come more than a month after Iran warned a different carrier - USS John C. Stennis - not to return to the Gulf.
Iran has threatened to close the Strait of Hormuz, a major oil shipping lane, amid rising tensions with the West over Tehran's nuclear program.
On Tuesday aircraft carrier USS Abraham Lincoln - part of the Bahrain-based U.S. Fifth Fleet - transited through the Strait of Hormuz with the Cape St. George destroyer behind it. CBS correspondent Allen Pizzey reports from aboard the St. George.
The USS Cape St. George's 500-person crew is on full alert. Helicopters patrol the flank. The Iranian navy is no match for the vast firepower of the Americans, but they're not helpless, says the ship's captain.
"The biggest concern out here is just the number of small fast-attack craft that the Iranians have built up over 20 years," Captain Don Gabrielson said. "They have, you know, a couple of thousand of them available."
More than 17,000 tankers pass through the 60 mile-long waterway every year and each one of them is vulnerable to attack.
The waterway is clogged with maritime commerce, anchors, cargo ships, fishermen and smugglers among which the Iranians can hide suicide bomb speed boats.
That's why gunner's mate Gullikson mans a 50 caliber machine gun.
"We're looking for small boat and aircraft, anything that might be getting close to us," Gullikson said.
Capt. Gabrielson added, "You know 'usual here' means there's always some level of tension. There's always some level of friction between everybody that's in the neighborhood."
Iranian navy ships regularly come close to the American vessels.
Just recently, the USS Cape St. George had a scare when it looked like an Iranian ship might have missiles aboard - but it turned out to just be exhaust pipes and a crane. A sigh of relief for Capt. Gabrielson.