The Navy destroyer USS Mason fired countermeasures in the Red Sea on Saturday after it detected what it believed were incoming missiles.
Officials Saturday night were uncertain about what exactly happened, if there were multiple incoming missiles or if there was a malfunction with the radar detection system on the destroyer.
"We are aware of the reports and we are assessing the situation. All of our ships and crews are safe and unharmed," one US defense official told CNN.
The USS Nitze and the USS Ponce were sailing nearby.
There are initial unconfirmed reports of missiles possibly being fired from positions both ashore on Yemen and by small spotter boats operated by Houthi rebels.
The incident was revealed Saturday by Chief of Naval Operations John Richardson during a ship christening in Baltimore.
Earlier Saturday night, a second US defense official said there were multiple incoming surface-to-surface missiles detected by the Mason.
In reaction, the Mason fired multiple missiles using onboard countermeasures, the two officials said.
NBC News first reported the incident.
Early Thursday, the US launched tomahawk cruise missiles into Yemen targeting radar sites in Houthi-held territory, sites the US claims were used to launch missiles in two previous incidents this week.