A Brit is reported to be among the dead after a seal-watching boat carrying 41 passengers capsized in rough waters off Cape Town.
At least two people are thought to have died and dozens injured as those onboard were thrown into the sea.
One British woman is believed to have been found alive inside the upturned catamaran, having survived for two hours in air pocket.
Rescue divers heard passengers calling for help and tapping back from inside of the boat while responding to the accident, bringing in specialist hydraulic cutting equipment to free those trapped by cutting through the hull.
More survivors were rescued after holding on to the main body of the 36ft long vessel which overturned about three miles off the coast of Cape Town. However, the search was called off for the day late on Saturday evening as visibility worsened.
Foreign Office: “The situation remains confused but we know that there are British Nationals involved and we are doing all we can to assist those who need it”
Called the Miroshga, the boat tipped over as it carried tourists from the fishing port of Hout Bay to Duiker Island, known for its large seal colony.
The locally-owned motorised boat also runs regular whale, dolphin and seal watching tours.
A spokesperson for the Foreign Office said: “We are aware that a boat has capsized in Hout Bay, Cape Town.
“We are in close touch with the authorities, and our Consul General has visited the port.
“The situation remains confused but we know that there are British Nationals involved and we are doing all we can to assist those who need it.”
Craig Lambinon, a spokesman for the National Sea and Rescue Institute, said: “We recovered one person out of the hull, who has been hospitalised in a stable but serious condition.
“Two local passenger boats, who were in the vicinity, managed to pick up most of the passengers from the water. But when the rescue divers got there they tapped on the catarmaran’s hull. They heard someone tapping back.
“They used the “jaws of life” to open up the hull and managed to rescue a woman from inside. She had been clinging to the inside of the hull.
“Subsequently another two women were rescued from inside the hull this way. All of them have now been taken to hospital.”