The maneuvers with 15 warships and more than 100 aircraft were sure to heighten tensions with Iran, which has frequently condemned the U.S. military presence off its coast and is in a faceoff with the West over its nuclear program and its capture of a British naval team.
While they would not say when the war games were planned, U.S. commanders insisted the exercises were not a direct response to Friday's seizure of the 15 British sailors and marines, but they also made clear that the flexing of the Navy's military might was intended as a warning.
"If there is strong presence, then it sends a clear message that you better be careful about trying to intimidate others," said Capt. Bradley Johanson, commander of the Stennis.
"Iran has adopted a very escalatory posture with the things that they have done," he added.
The exercises began four days after Iranian forces detained the 15 Britons for allegedly being in Iranian territorial waters near the northern end of the Gulf. U.S. and British officials insist the team was properly searching cargo vessels inside Iraqi waters.
F/A-18 fighter jets roared off the Stennis' flight deck all day, mounting a dozen rapid-fire training sorties against imaginary enemy ships and aircraft. A second task force with the carrier USS Dwight D. Eisenhower also took part in the drills.
"These maneuvers demonstrate our flexibility and capability to respond to threats to maritime security," said Navy Lt. John Perkins, 32, of Louisville, Ky., as the Stennis cruised about 80 miles off the United Arab Emirates after entering the Persian Gulf overnight.
"They're showing we can keep the maritime environment safe and the vital link to the global economy open."
At the headquarters of the Navy's 5th Fleet in Bahrain, Cmdr. Kevin Aandahl said the maneuvers would last several days. He said U.S. warships would stay out of Iran's territorial waters, which extend 12 miles off the Iranian coast.
None of America's naval coalition partners in the region joined the maneuvers.
A French naval strike group, led by the aircraft carrier Charles de Gaulle, was operating just outside the Gulf in the Arabian Sea. But the French ships were supporting NATO forces in Afghanistan and not taking part in the U.S. maneuvers, Aandahl said.