Tensions in the Gulf region mounted Friday as Washington claimed an Iranian drone was destroyed after threatening an American naval vessel at the entrance of the Strait of Hormuz.
It was believed to be the first US military engagement with Iran following a series of increasingly serious incidents.
The USS Boxer, an amphibious assault ship, "took defensive action" against the Iranian drone on Thursday to "ensure the safety of the ship and its crew," Pentagon spokesman Jonathan Hoffman said.
The drone was "immediately destroyed" after it approached within 1,000 yards (914 meters) of the Boxer, US President Donald Trump told reporters.
"This is the latest of many provocative and hostile actions by Iran, against vessels operating in international waters," he added.