ATHENS, Greece — Hopes are fading in Greece that rescue workers will find survivors after a train collision killed dozens of people on Tuesday night.

Emergency services say at least 36 people were killed in the head-on crash between a freight train and a passenger train near the city of Larissa.

The death toll is likely to rise as more victims are identified. This could take time as DNA analysis will be required, given the level of destruction in the front carriages caused by the crash and a subsequent fire, state broadcaster ERT reported.

Seventy-two people were taken to hospital, some of them with serious injuries.

There were 342 passengers and 10 railroad employees on the passenger train from Athens to Thessaloniki plus two drivers on the freight train.

Greek Prime Minister Kyriakos Mitsotakis called the accident an “unspeakable tragedy” as he visited the scene at midday. Visibly moved, he promised that the cause of the accident would be fully investigated.

The main task is to treat the wounded and identify the bodies, he said, adding that everything possible would be done to ensure that nothing like this ever happens again.

Transport Minister Kostas Karamanlis promised that no findings would be kept secret.

The Greek government has ordered three days of national mourning for the victims.

Rescue workers were using cranes and other heavy equipment to try and lift the derailed train cars to search for survivors, according to reporters at the crash site near Larissa. Images showed that the front two cars of each train had been destroyed and burnt out.

The passenger train collided head-on with a commercial train traveling on the same track. The passenger train, the Inter City 62, had departed from the Greek capital at 7:22 pm (1722 GMT) on Tuesday evening.

Some 350 passengers were said to have been on board.

“I thought I was going to die,” one passenger told Kathimerini daily newspaper. He said he had been sitting in one of the rear carriages.

He had sought shelter on the ground, he said. People were screaming and crying. Other passengers reported that they had been able to break the windows and escape in the dark from the half-turned over carriage.

“There was chaos and incredible noise,” a survivor told state broadcaster ERT.

In Larissa, many people came to give blood following an appeal by the Greek Red Cross and hospitals in the area.

Some 200 passengers who were not injured or suffered only slight injuries were taken by bus from the scene of the accident to Thessaloniki, 150 kilometers away.

In Thessaloniki, the authorities set up telephone hotlines, as relatives waited fearfully for news.

Many of the passengers were reportedly students who were heading to the University of Thessaloniki after a longer holiday weekend.

The cause of the accident was unclear, although initial speculation points to human error.

According to media reports, the electronic guidance system on the track was not working. There had been problems with it for some time, leaving staff to decide on some stretches which track the trains should go on.

The crash occurred on a line connecting Athens with Thessaloniki that was modernized over the past years.

The railway official responsible for the line was arrested following the crash, ERT reported.

Despite the modernization, which included new tunnels and bridges as well as two tracks along the 500-kilometer route, there were still significant problems with the electric coordination of traffic control, according to the Greek train drivers’ union.

“We travel from one part of the line to the next by radio, just like in the old days. The station managers give us the green light,” the union’s president Kostas Genidounias explained on state radio.

Greece’s railway, Hellenic Train, is operated by Italy’s state-owned railway company Ferrovie dello Stato Italiane.

Condolences came in from many countries, and Turkish Foreign Minister Mevlüt Cavusoglu spoke on the phone with his Greek counterpart Nikos Dendias.

European Commission President Ursula von der Leyen and European Parliament President Roberta Metsola expressed their condolences.

“The whole of Europe is mourning with you,” von der Leyen wrote on Twitter.

“My thoughts are with the people of Greece after the terrible train accident that claimed so many lives last night near Larissa,” the commission president wrote.

“My sincere condolences to all victims, their families and friends,” Metsola wrote on Twitter.

“Grateful to all rescuers and medical staff on site,” she added.