A 183-foot sailboat carrying 22 people sank early on Monday off the coast of the Italian island of Sicily following stormy weather in the area, killing at least one passenger, according to Italian officials.
Members of the coast guard have rescued 15 passengers, but six -- including two Americans -- are still missing, according to the coast guard and a local port authority. British and Canadian citizens are also unaccounted for, the coast guard said in a statement.
Of those recovered, eight have been transported to local hospitals, officials said.
The U.K.-flagged vessel -- named the Bayesian -- sank off Porticello, near the coastal city of Palermo, the statement said. The ship is currently located at a depth of around 164 feet, with firefighter divers now attempting to reach it, the statement said.
One body was recovered and six people were missing, an authority from the Palermo Port Authorities told ABC News. Divers reached the hull of the ship early on Monday and were still searching the water, the official said.
A State Department spokesperson said U.S. officials "are aware of reports that U.S. citizens were on the Bayesian."
"We are working with local authorities to gather information and we stand ready to provide consular assistance," the spokesperson said.
Four coast guard vessels, one helicopter and a team of fire brigade divers are involved in the search, which is being coordinated by the Palermo coast guard, the statement said.
Fabio La Bianca, who owns the local BAIA Santa Nicolicchia restaurant, told ABC News that he noticed the moored vessel had disappeared when he went to check on storm damage to his business.
"After half an hour with the other guys we realized that it was no longer there and immediately the rescuers were going around to look for the missing, they had also launched two distress rockets in the air before," La Bianca said.
Local Mayor Giuseppe D'Agostino wrote on Facebook that the "tragedy that struck our community is unparalleled in history."
"The administration has activated all channels with the police and is taking care of the people recovered alive so far," D'Agostino said, adding that local authorities are gathering clothes and finding accommodation for the survivors.
"The search continues at sea and all we can do is pray and hope to find someone alive."
ABC News' Joe Simonetti and Shannon K. Kingston contributed to this report.