One person has died and six others are missing after a luxury yacht capsized off the coast of Sicily early Monday morning.
The 56 m (183 ft) vessel was carrying 22 people – 10 crew and 12 passengers – including British, American and Canadian nationals.
Emergency services have rescued 15 people, including a British one-year-old girl.
Local media reported that the boat, named Bayesian, sank after encountering a heavy storm overnight that caused water jets, or swirling columns of air, to appear over the sea.
Witnesses told Italian news agency Ansa that the Bayesian’s anchor dropped when the storm hit, the mast broke and the ship lost balance and sank.
A waterspout is similar to a hurricane and can form in oceans, seas, or large lakes.
Divers have identified a wreck at a depth of 50 meters and are searching for missing people.
A man’s body was found outside the rubble. His citizenship has not been confirmed.
15 people were rescued safely after the storm hit.
In the initial aftermath, a nearby Dutch-flagged ship picked up survivors from the waves and protected them until emergency services arrived.
Capt. Carsten Borner said that after the storm passed, the crew noticed that the trailing boat had disappeared.
“We saw a red volcano, so my first mate and I went over there and saw this life raft floating,” he told Reuters.
The lift rafter carried 15 survivors, three of whom were “severely injured,” he said.
A local fisherman told Reuters news agency that he saw people being rescued by an inflatable raft sent from another boat.
The captain of a local fishing trawler said he saw debris from the deck, including mattresses, floating in the sea.
Footage from the wreck site showed helicopters hovering over several Coast Guard vessels as divers dressed in bright orange descended into the water.
A one-year-old British girl was brought ashore by a firefighter and handed over to authorities to be taken to hospital, Italian newspaper Corriere della Serra reported, citing a hospital official.
The teenager has undergone tests but is said to be fine.
Eight of those rescued are being treated in hospital, the Italian coast guard said.
The western part of the Mediterranean has been hit by heavy storms since the middle of last week.
On Sunday night and into Monday morning, bad weather passed along the northern coast of Sicily.
BBC weather forecaster Matt Taylor said: “A waterspout is a cyclone that occurs over water rather than land.
“They can form at the base of cumulonimbus/thunder clouds during intense storms.
“Turbulence, and wind blowing in slightly different directions around the cloud, can cause rotation at the base of the cloud and droplet formation.
“Like hurricanes, they bring powerful winds, but instead of picking up dust and debris, they create water mist around the rotating air column.”
The UK Foreign Office said it was aware of the incident and was in contact with local authorities.
Bayesian Camper and managed by Nicholsons International.
A spokesman told BBC Verify: “Our priority is to assist with the ongoing search and provide all necessary support to the rescued passengers and crew.”