A huge bomb has devastated Bologna railway station, killing at least 75 people.
The device exploded at 1025 local time (0825 GMT) in the air-conditioned waiting room, which was crowded with people trying to escape the heat.
Most of the victims of the blast were Italian, but it is believed some foreign tourists were among the dead. More than 200 people were also injured.
A neo-fascist group rang a Rome newspaper three hours after the attack to say it planted the bomb, but similar claims have also been made by the far-left Red Brigade.
"People were coming out of the station with blood streaming from their wounds".
Witness Simon Gray, University professor Malcolm Quantrill said he had just reached a ticket window in the booking hall when he saw a "flash of yellow light".
The 44-year-old Londoner said: "I did not hear an explosion - just the crash of the masonry falling and the sound of breaking glass as the ticket window disintegrated.
"There was blood all over me. Everyone was running, shouting and screaming."
Another witness, Simon Gray, 22, said a 150-foot (46 m) section of the facade of the railway station collapsed in the blast.
The British tourist, from Birmingham, told reporters: "People were coming out of the station with blood streaming from their wounds.
"One middle-aged man was carried to an ambulance with blood pouring from a severed leg."
The second-class waiting room where the device was planted was destroyed, as was an adjoining restaurant.
Over a thousand rescuers are now searching the remains of the station for people trapped under the rubble.
Troops cordoned off the area, but dozens of people who had rushed to the scene managed to get into the wrecked buildings to search for relatives and friends.
The bombing comes on the same day a Bologna court sent eight men, including well-known neo-fascist Mario Tutti, to trial for another railway attack six years ago.
That explosion on the Italicus Express from Rome to Brenner on 4 August 1974 killed 12 people.