Houthi rebels in Yemen have released a video that they say shows their fighters hijacking a cargo ship in the Red Sea.
The British-owned Galaxy Leader was seized while sailing near Yemen on Sunday. It is operated by Nippon Yusen, a Japanese firm also known as NYK Line.
The situation of the ship's 25 crew members is unknown.
The Houthis posted the video on social media on Monday. It shows a helicopter approaching the cargo ship from behind. About 10 armed fighters can be seen on the ship.
The video shows the fighters pointing their guns and restraining the crew. They can be heard shouting, "Death to Israel. Death to America."
The footage also shows several small boats surrounding the cargo ship.
The Houthis say the ship is Israeli, a claim denied by Israel's military. But Haaretz and other Israeli media outlets say the ship is owned by a company affiliated with a wealthy business person from the country.
US State Department spokesperson Matthew Miller said on Monday that the seizure of Galaxy Leader is a "flagrant violation of international law."
He said the United States demands the immediate release of the ship and its crew.
Iran-backed Houthis have declared their support for Hamas, and have repeatedly launched missiles and drones into Israel since the current conflict began.
The Houthis have threatened to continue targeting ships owned or related to Israel.