Thai navy said, they are trying to locate 33 marines, who got missing after a corvette sank overnight in choppy waters in the Gulf of Thailand.
The That military has deployed warships and helicopters on Monday to start their hunt.
3 navy vessels and 2 helicopters were sent to find the missing.
They navy authorities said, in an overnight rescue mission they secured 73 of the 106 people aboard, with the remaining 33 forced to abandon ship.
The navy posted images and video footage on its Twitter account showing a group of personnel in orange vests in a black inflatable raft moving away from a ship in darkness as waves swelled around it. It was not immediately clear how many rafts had been deployed.