US citizens among Sicily superyacht missing as search continues

Two Americans are among the six people still missing after a superyacht sank off the coast of Sicily on Monday, ABC News has confirmed.

Christopher and Neda Morvillo are among those still unaccounted for who were aboard the U.K.-flagged vessel, named Bayesian, which sank during a violent storm.

Christopher Morvillo is a partner at law firm Clifford Chance and represented the yacht’s owner -- British tech tycoon Mike Lynch -- in his recent fraud case brought by Hewlett Packard. He is a former assistant United States attorney for the Southern District of New York .

"We are in shock and deeply saddened by this tragic incident," Clifford Chance said in a statement. "Our thoughts are with our Partner, Christopher Morvillo, and his wife Neda who are among the missing. Our utmost priority is providing support to the family as well as our colleague Ayla Ronald, who together with her partner, thankfully survived the incident. Our thoughts extend to the other passengers and crew and all those affected."

Divers are "assessing the feasibility of safely entering the wreck, an operation complicated by the depth and position of the hull lying on the seabed at about 50 meters, half a mile from the port of Porticello," the Palermo coast guard said.

Divers, helicopters and patrol boats are all participating in search and rescue efforts, the coast guard said.

The search resumed Tuesday morning. Among the bodies that may be trapped inside the vessel are those of Lynch and his 18-year-old daughter Hannah.

Some of the 15 people who were rescued are either still recovering or have now left hospital.

"The search for the six missing passengers is therefore continuing unabated, with divers assessing the feasibility of safely entering the wreck, an operation complicated by the depth and position of the hull lying on the seabed at about 50 metres, half a mile from the port of Porticello. At the moment there are no traces of oil pollution," the Palermo Coast Guard said.

ABC News’ Aicha El Hammar, Helena Skinner, Phoebe Natanson and Joe Simonetti contributed to this report.