The group's move through the strategic waterway separating Iran and the United Arab Emirates towards the Gulf was scheduled, and unfolded without incident, the US Navy said in a statement.

The strait is a chokepoint for a third of the world's seaborne oil.

A Pentagon official who spoke on condition of anonymity said exchanges between US forces and Iran's coast guard were "safe and professional."

It was the first time a US aircraft carrier group went through the strait since Iran downed a US drone in June in the same area.

Also in June, two foreign tankers were attacked in the area. Those attacks were blamed on Iran, though it denied involvement.

The last time a US aircraft carrier transited the strait was in April, the Pentagon official said.

The Strait of Hormuz is particularly vulnerable because it is very narrow -- about 50 kilometers (30 miles) wide -- and not very deep.

Iran, which has a sophisticated military and controls much of the oil shipping lanes through the Strait of Hormuz, regularly threatens to shut it down if its enemies, such as the United States, commit hostile acts.