The Pentagon is warning whomever fired missiles at a US Navy destroyer and an accompanying ship off the coast of Yemen over the weekend had done so "at their own peril", language that suggested preparations for possible retaliation.
The USS Mason was targeted in a failed missile attack from within the Iran-aligned Houthi rebel held territory on October 10.
Pentagon spokesman Captain Jeff Davis told a news briefing on Tuesday: "Anybody who takes action, fires against US Navy ships operating in international waters, does so at their own peril,"
When asked whether the Pentagon was developing targets for retaliatory strikes, Davis said "I'm not confirming that right now".
On Monday the USS Mason detected two inbound missiles within the space of an hour while in the Red Sea however both missiles hit the water before reaching the ship.
"There were no injuries to our sailors and no damage to the ship," Mr Davis said on Monday.
Saudi Arabia and the United States blame Shi'ite Iran for supplying weapons to the Houthis. Tehran views the Houthis, who are from a Shi'ite sect, as the legitimate authority in Yemen but denies it supplies them with weapons.
A US defence official said the first missile triggered counter-measures from the USS Mason. It was not immediately clear whether those defences may have helped prevent a direct hit on the ship.
The USS Mason did not return fire, the official said, adding that the incident took place just north of the Bab al-Mandab strait off Yemen's southern coast.