Palermo Prosecutor Piero Grasso told The Associated Press that 23 people survived and were taken off rescue boats on stretchers at Palermo's port. Some survivors clung to the plane's wings in rough seas while waiting for rescuers to arrive, media reports said.
Grasso said 13 people were confirmed dead and three were missing. He said the toll of 19 he reported earlier was based on overlapping information from several rescue groups, including the fire department, coast guard and border police.
"There are no bodies in the wreckage," Grasso said.
He added that the fuselage of the ATR-72 was being towed to shore.
"Some people were on the wing, screaming, yelling for help," said Filippo Morgante, an official at Palermo fire department operations center, which sent boats out for the rescue."
"Others were on the fuselage, and some were trapped inside the plane," Morgante said by telephone. "Some weren't wearing lifejackets. Maybe they didn't have the time to put them on."
Palermo port official Vincenzo Pace told SKY TG24 TV that some bodies were found several miles from the wreckage, apparently having been carried away in rough seas.
Nine survivors were reported in serious condition. At least three crewmembers survived.
Grasso said the twin-propeller plane was forced to make a water landing about eight miles off Sicily because of a "technical problem" that was being investigated by authorities and Italy's ENAV air safety agency.
"We can rule out terrorism," Grasso said.
The plane left Bari, Italy, on its way to Djerba, Tunisia. It was operated by Tuninter, an affiliate of Tunisair, the national airline of Tunisia. Tuninter said it had no immediate word on victims.
"The plane had engine problems and was trying to (emergency) land in Palermo and had to land in the sea," ENAV spokeswoman Nicoletta Tommessile told the AP.
The plane's crew contacted the Rome airport tower at 3:24 p.m. to report engine trouble and say they would have to land at Palermo's airport. Sixteen minutes later, the plane's crew told tower officials: "We're ditching in the sea," Tommessile said.
Palermo fire official Giovanni Saccone said when rescuers arrived, the plane was still floating. Hours later, the tail broke off and fire department divers worked to keep the wreckage afloat.
Nine of the survivors were in serious condition, said Capt. Giuseppe Averna, an official with the sea division of Italy's border police. One survivor was a young girl, said Giuseppe Pumilia, an emergency room doctor at Palermo's Villa Sofia hospital, where five survivors were taken.
Three crewmembers were among the survivors at Palermo's Civic Hospital, officials said.
Tunisian officials said all the passengers were Italian, and SKY said most of them were from the Puglia region in the heel of the boot-shaped Italian peninsula.
The ATR-72, which was built in France, has a two-person crew and seats up to 74 passengers. Its maiden flight was in 1988.