The US says three commercial ships have been attacked by missiles in the Red Sea - with one of its destroyers shooting down armed drones as it went to help.
The Bahamas-flagged Unity Explorer, owned by a British company, was one of the vessels targeted in the drone and missile assault on Sunday and suffered minor damage, US military Central Command said.
Israel said the ships are not connected to the country.
It potentially marks a major escalation in a series of maritime attacks linked to the Israel-Hamas war.
US Central Command said the attacks had been "fully enabled by Iran", adding that the US would "consider all appropriate responses".
"These attacks represent a direct threat to international commerce and maritime security," it said in a statement.
"They have jeopardised the lives of international crews representing multiple countries around the world.
"We also have every reason to believe that these attacks, while launched by the Houthis in Yemen, are fully enabled by Iran."
US Central Command said all the ships attacked were in international waters and that the USS Carney went to help after receiving distress calls and shot down three drones.
The first attack was at about 9.15am local time, when the Carney detected a missile fired from Yemen towards the cargo ship M/V Unity Explorer.
The missile landed "in the vicinity of the vessel", according to the US, which said the ship is "UK-owned and operated" and has crew from two countries - which it didn't name.
At about 12pm, the American ship shot down a drone - again launched from Houthi areas of Yemen. The US said it was headed towards the Carney but that its final target was unclear.
"We cannot assess at this time whether the Carney was a target of the UAVs," said US Central Command.
About half an hour later, the M/V Unity Explorer was attacked by a second missile - which this time hit the ship and caused "minor damage", according to the US.
While assessing the damage, another drone was detected and shot down by the USS Carney.
The second vessel attacked was another large cargo ship, M/V Number 9, described as "Bermuda and UK owned and operated", at about 3.30pm.
It was also hit by a missile from Houthi-controlled areas of Yemen, said Central Command - which posted the timeline on X, formerly Twitter - and said no damage or casualties were reported.
The third ship attacked was the M/V Sophie II - which was hit by a missile and sent a distress call at about 4.30pm.
USS Carney shot down a third drone "headed in its direction" as it went to help, said US Central Command.
It said the M/V Sophie II had a crew from eight countries and was a Panamanian-flagged bulk carrier.
The Number 9 reported some damage with the Sophie II suffering no significant damage, according to Central Command.
Houthi spokesperson, Brigadier General Yahya Saree, claimed responsibility for attacking the Unity Explorer and M/V Number 9.
He claimed they were targeted after rejected warnings from its navy.
"The Yemeni armed forces continue to prevent Israeli ships from navigating the Red Sea (and the Gulf of Aden) until the Israeli aggression against our steadfast brothers in the Gaza Strip stops," he said.
"The Yemeni armed forces renew their warning to all Israeli ships or those associated with Israelis that they will become a legitimate target if they violate what is stated in this statement."
The Houthis are an ally of Iran and control most of Yemen's Red Sea coast.
They have previously fired ballistic missiles and armed drones at Israel and vowed to target more Israeli vessels.
Last month, an Israeli-linked cargo ship was seized by Houthi militants.
An Israel Defence Forces spokesman, Rear Admiral Daniel Hagari, said the ships attacked had no connection to Israel.
Speaking before the US statement, he said missiles had been fired at two commercial vessels and one was "significantly damaged".
"It is in distress and apparently is in danger of sinking, and another ship was lightly damaged," he said.