The attempted hijacking of a commercial vessel off the coast of Yemen on Sunday was carried out by Somali pirates, not the Houthi rebels, the Pentagon said.
The incident in the Gulf of Aden happened before missiles were fired from Houthi-controlled territory in Yemen.
A US Navy warship responded to a distress call from the chemical tanker Central Park on Sunday. The attackers were taken aboard American destroyer the USS Mason and the Central Park and its crew are safe, the US military said.
"We're continuing to assess, but initial indications are that these five individuals are Somali," Pentagon spokesman Brig Gen Patrick Ryder said on Monday, adding that it was "clearly a piracy-related incident".
The Central Park tanker is managed by Zodiac Maritime, an international ship management company with its headquarters in the UK. The company is owned by an Israeli magnate.
The Liberian-flagged vessel was built in 2015 and is owned by Clumvez Shipping, LSEG data showed.
The US Navy fired warning shots when the attackers tried to escape, Brig Gen Ryder said. No injuries were reported.
Two ballistic missiles were later fired from Houthi-controlled territory in the general direction of the USS Mason and Central Park, the military said.
"It's not clear to us who they were targeting exactly," Brig Gen Ryder said.
The attempted tanker hijacking followed the seizure last week of an Israeli-linked cargo ship by the Iran-backed Houthis, in the southern Red Sea. It was the latest in a series of attacks on regional waters following the outbreak of the Israel-Gaza war.