Rescue workers in the Italian port of Genoa are looking for six people missing after a container ship rammed into a control tower, which then collapsed.
Two coastguard officials and a pilot for the port were killed. Four people were injured.
It is thought others may have been trapped in a lift and fallen into the water.
Staff were changing shifts at the time so more people than usual were in the tower.
“The main injuries are obviously broken bones, injuries due to crushing, a serious chest injury… the wounded have been evacuated on “red alert” to hospitals in Genoa,” said Andrea Furgani, a doctor working with the emergency services.
“Of the six who are missing there is a very low probability that any are in this part of the building and not in the part which fell into the water,” said fire brigade spokeswoman Alessandra D’Errico.
The control tower was more than 50 metres high. The container ship that struck it, the Jolly Nero, is more than 200 metres long and weighs over 40,000 tonnes.
Amid the rescue operation during the night a call went out from a mobile under the debris but it was interrupted before it could be traced.
An investigation has been opened into the cause of the accident.