The Iran-backed Houthi movement of Yemen hijacked a United Arab Emirates-flagged cargo vessel which it claimed was engaged in "hostile acts".
The ship was heading to the Saudi port of Jizan, just north of Yemen, from the Yemeni Red Sea island of Socotra when it was attacked just before midnight on Sunday, Saudi state news agency SPA reported, quoting coalition spokesman Brigadier General Turki al-Malki.
Saudi Arabia has been battling the Houthis for more than six years. The alliance has accused the Houthis of attacking shipping in the Red Sea, one of the world's busiest maritime lanes leading to the Suez Canal.
The Houthis' military spokesman, Yahya Sarea, confirmed seizure of the vessel which he said was carrying military equipment and engaged in "hostile acts targeting the security and stability of the Yemeni people". He added that the crew, "of different nationalities", were still on board.
In a TV press briefing, Sarea shared photos and videos that he said came from ship showing armored vehicles, weapons and ammunition. He added the vessel had been taken to the Houthi-controlled port of Salif, north of Hodeidah.
SPA said the vessel was carrying equipment from a shuttered field hospital.
The United Kingdom Maritime Trade Operations (UKMTO) said late on Sunday it had received reports of an attack on a vessel in the Red Sea.
Reporting by Reuters