Two rail workers were killed and about 30 people injured on Thursday when a high-speed train derailed before dawn near Milan in northern Italy, authorities said.

The crash occurred just after 5:30 am (4:30 GMT) near the town of Lodi, about 50 kilometres (30 miles) south of Milan. "It was a serious accident that had a tragic end with the death of two rail workers" aboard the train, Lodi Prefect Marcello Cardona told reporters, who added that an investigation was underway.

Cardona said none of the injuries suffered were life-threatening and all casualties had been taken to hospital. The Lombardy region's health department put the number of injured at 31.

"It could have been a lot worse," Cardona said, adding that there were only 33 people on board the train. Only one person was in the first car and two people in the second when the accident occurred, he said.

While noting that all possible causes were being investigated, Lodi prosecutor Domenico Chiaro said that "the train derailed near a railroad switch that was supposed to be in a position but was not."

"I thought I was dead," a survivor told local newspaper Liberta from hospital in Piacenza where he was being treated for minor injuries. "I closed my eyes and prayed."

"The train was going very fast, perhaps 300 kilometres per hour (around 200 miles per hour)," said the unnamed man in his 20s.

"Suddenly, I felt a violent blow. A really loud roar," said the man who was travelling with a friend in the second carriage.

"We held hands tightly to avoid falling. The wagon overturned and while waiting for help we went out through a hole to save ourselves," he said, adding that they were stuck on the crashed train for 15 minutes. Two helicopters, hundreds of firemen, police and other authorities descended on the open farmland area outside of Lodi.