Hospital officials in the nearby town of Larissa said at least 25 people had serious injuries.

“The evacuation process is ongoing and being carried out under very difficult conditions due to the severity of the collision between the two trains,” said Vassilis Varthakoyiannis, a spokesman for the Greek fire service.

Survivors said several passengers were flung through the train car windows by the impact. They said others fought to free themselves after the passenger train gave way and crashed into a field next to the track.

Rescue workers with headlamps worked in thick smoke, pulling pieces of mutilated metal from the cars to search for trapped people. Others scanned the field with flashlights and checked under the wreckage.

Passengers who were slightly injured or unharmed were bussed to Thessaloniki, 130 kilometers (80 mi) to the north. Police took down their names when they arrived in an effort to track down any missing.

A surviving teenager who did not give his name told Greek reporters as he got off one of the buses that just before the crash he felt a strong brake and saw sparks and then suddenly stopped.

“Our carriage didn’t derail, but those in front of us did derail and were destroyed,” he said, visibly shaken.

He added that the first car caught fire and that he used a bag to smash the window of his car, the fourth, and escape.

Railway operator Hellenic Train said the northbound passenger train from Athens to Thessaloniki, Greece’s second-largest city, had about 350 passengers on board.

In comments on state television, Costas Agorastos, the regional governor of the Thessaly area, described the clash as “very powerful” and said it was “a terrible night”.

“The front part of the train was destroyed. … We bring in cranes and special lifting equipment clears the rubble and lifts the train cars. Debris is being thrown all around the crash site.”

Officials said the military had been contacted to assist.

Hellenic Train is operated by the Italian FS Group, which provides rail services in several European countries.

Gatopoulos reported from Athens.