Warships and aircraft from the US, France, Belgium and Japan are taking part in joint exercises in the Arabian Sea and Gulf of Oman.
This year’s war games, known as Group Arabian Sea Warfare Exercise, or Gaswex, aim to enhance mutual capabilities in maritime security, the US Navy said.
Participants include ships and aircraft from the French Charles de Gaulle carrier strike group, auxiliary ship FS Var, frigates FS Provence and FS Chevalier Paul, Belgian frigate HNLMS Leopold I and Japanese destroyer JS Ariake.
US forces include the Makin Island Amphibious Ready Group with 15th Marine Expeditionary Unit, guided-missile cruiser USS Port Royal and aircraft including F-35, P-8, MH-60, Air Force F-16s, E-3 and tankers.
“By co-operatively training together, exercises like this allow participating naval forces to effectively develop the necessary skills to address threats to regional security, freedom of navigation and the free flow of commerce,” the US Navy said.
It is one of many exercises in which the US military participates with partner nations in the US Central Command area of responsibility each year.
Iran abandoned all limits of its 2015 nuclear deal with world powers after former president Donald Trump unilaterally withdrew the US from the accord in 2018.
President Joe Biden has expressed a desire to return to the deal if Iran honours the accord’s limits on the Iranian nuclear programme. But tension remains high because militias in Iraq, probably backed by Tehran, continue to take aim at US interests.
Last month, Mr Biden launched an air strike on Syria in retaliation.
There was no immediate reaction from Iran to the naval drill.