The Red Sea and the nearby strategic Bab el-Mandeb strait, a crucial chokepoint for international shipping and crude oil, has been the scene of what the U.S. describes as at least two missile attacks from rebel-held territory in Yemen. American forces have fired back once with Tomahawk missiles, destroying mobile radar positions in the first shots fired by the U.S. in anger in the stalemated conflict.

In the latest incident, a group of American warships in the Red Sea on Saturday night "had indications of a possible inbound missile threat and deployed appropriate defensive measures," said Capt. Paula Dunn, a spokeswoman for U.S. Navy Forces Central Command. She said in a statement that all ships and sailors were safe, without elaborating.