At least three people have died and up to six are missing after a ship crashed into a control tower in the Italian port of Genoa, reports say. Part of the tower is said to have crashed into the water when it was hit by the Jolly Nero container ship. About 10 people were in the tower at the time of the accident. Four people have been taken to hospital, but others are feared to be in the water or trapped inside the tower. The crash triggered a frantic night-time search operation in the waters around the tower. The cause of the crash - whether human error or mechanical fault - has not yet been confirmed. The ship's owner, Stefano Messina, who arrived at the port soon after the crash, had tears in his eyes as he told journalists: "We are all utterly shocked. Nothing like this has ever happened before, we are desperate." One of the victims was thought to be a woman in her 30s, while the other two were male. "It's a terrible tragedy. We're in turmoil, speechless," Port Authority President Luigi Merlo told local TV. Emergency services said it was not clear whether those still missing were trapped in the lift which had fallen into the water or were in the sea itself, reports said. The accident is said to have occurred at about 23:00 on Tuesday night (21:00 GMT), when a shift change was taking place in the control tower - meaning more people were inside. The Coast Guard and Port Authority were both said to have staff working inside the tower. The ship was manoeuvring out of the port with the help of tugboats in calm conditions, reports said. The huge tower was bent by the impact of the collision and part of it reportedly fell into the sea. Genoa's prosecutor is investigating the incident, Corriere Della Sera newspaper says. The ship has been impounded and the captain is being questioned. The Jolly Nero is almost 240 metres (787 feet) long and weighs over 40,500 tonnes. It is owned by the Italian firm Ignazio Messina & Co. It was bound for Messina, Sicily, at the time of the crash, reports say.