Nine people were feared dead on Wednesday after a container ship crashed in Italy's busiest port of Genoa, bringing down a 50-metre (164-foot) control tower, in an accident that revived memories of last year's Costa Concordia cruise ship disaster.
The Jolly Nero ploughed into the dock late on Tuesday during a standard manoeuvre as it was being steered to exit the port on its way to Naples with a cargo of trucks and containers.
Some of the victims were thrown into the water, while others were trapped in the tower's lift, which plunged into the sea, emergency workers said.
"Seven people died, four were injured and two are missing," Transport Minister Maurizio Lupi told parliament after visiting the scene of the crash.
Prime Minister Enrico Letta also visited the site, as did the archbishop of Genoa Angelo Bagnasco, who is also head of the Italian Bishops' Conference.
"This is an immense tragedy," said Letta, who also visited the injured in hospital. Bagnasco said the incident had been "a blow to the heart".
The city will observe a day of mourning on Thursday and there will be a procession for the victims, several of them coast guard officials.
Earlier media reports that a 50-year-old man, a telephone operator, had been pulled alive from the rubble on Wednesday were not confirmed.
The man was officially listed among the fatalities.
Lupi said there were three possible explanations for the accident: engine failure, a problem with cables used by the two tug boats towing the ship, or bad steering and excessively high speed.
Prosecutors have placed the ship's captain and a port pilot who had been on board during the manoeuvre under investigation for multiple manslaughter and have impounded the ship.
Prosecutor Michele Di Lecce said at a press conference he was also looking into a possible charge of "attack on transport security" since the control tower oversaw maritime operations for the entire Liguria region of northwest Italy.
"We do not rule out other people being placed under investigation," he said.
ANSA news agency quoted a black box recording which appeared to indicate a technical malfunction since the ship was unable to stop reversing and could not be switched into a forward gear.
"There is no more water. What are you doing?" a tug boat captain is heard telling the port pilot on the radio, ANSA said.
"I don't have the gear!" the pilot responds.
The crash carried echoes of the Costa Concordia tragedy last year in which 32 people were killed when a luxury liner crashed into a Tuscan island.
The Costa Concordia had been performing a risky "salute" manoeuvre close to the island of Giglio and six people face charges of manslaughter including the captain, Francesco Schettino.
Daniele Bo, a spokesman for the Jolly Nero's owner Ignazio Messina & Co, told AFP: "It is so unexpected that it is inexplicable. It was a routine manoeuvre."
The company's fleet has been involved in a series of incidents around the world in recent years, including in South Africa and Egypt and Somali pirates attacked two of its ships in 2009.
A report in Il Fatto Quotidiano daily said the fleet had also been linked to episodes of toxic waste trafficking in the past.
The falling tower, erected in the 1990s, crushed two adjacent office buildings in the port -- which sees 6,600 ships transit each year, carrying more than 50 million tons of cargo.
The 1976-built ship was also being steered by two tug boats but Lupi stressed the captain still has ultimate responsibility during port manoeuvres.
The Italian ship, which was relatively undamaged, is almost 200 metres (655 feet) long, 30 metres wide, and has a gross tonnage of over 40,500.
The ship's owner, Stefano Messina, choked back tears as he told journalists at the scene of the crash: "We are all utterly shocked. Nothing like this has ever happened before, we are distraught."
Rescue divers were still searching the inky waters around the port. Others were using dogs trained to find people in earthquake zones to see if any survivors might be trapped under the rubble.
The crash happened during a shift change in the tower, which bent over by 45 degrees before falling into the water, leaving only an emergency staircase standing.