U.S. officials said the military launched cruise missile strikes to knock out radar sites in Yemen controlled by Iran-allied Huthi forces, retaliating after failed missile attacks this week on a U.S. Navy destroyer.
The strikes on October 13, authorized by President Barack Obama, were Washington's first direct military action against Huthi targets in the Yemen civil war.
The Pentagon stressed that the strikes were defensive and aimed at radar that enabled the launch of three missiles this week against the U.S. Navy destroyer USS Mason.
"These limited self-defense strikes were conducted to protect our personnel, our ships, and our freedom of navigation," Pentagon spokesman Peter Cook said.
"The United States will respond to any further threat to our ships and commercial traffic, as appropriate."
Huthi rebels deny they have targeted any warships.
A Saudi-led coalition is carrying out an air campaign against the Huthi rebels.
U.S. support for the coalition has come under strain following an air strike on a funeral in Sanaa last weekend killed 140 people.
Based on reporting by Reuters and dpa