In short:

Residents of a rural village in central Spain have rushed to help a massive emergency response after the most deadly rail disaster in Europe in more than a decade.

At least 68 people have died and dozens injured following a crash involving two high-speed trains travelling between Madrid and Seville.

What's next?

Spain has declared three days of national mourning as investigations continue into how the collision unfolded.

Residents of a rural village in central Spain have rallied into action to help a massive emergency response following the most deadly rail disaster in Europe in more than a decade.

At least 68 people were killed and dozens more injured in the Toledo province on Wednesday, local time, when two high-speed trains collided while carrying hundreds of passengers between Madrid and Seville.

A train operated by the state-owned RENFE company struck the rear of another train operated by private company IRYO that was stopped.

Loading...The collision derailed two carriages on the tail of the IRYO train and the front of the RENFE train.

The crash occurred on a flat stretch surrounded by olive fields between the villages of Urda and Los Yébenes, shredding carriages into bits of metal and other material.

Debris was scattered down a gravel slope.

In Urda, 78-year-old pharmacist Antonioa Garcia told Reuters he was among the first on the scene, jumping into his car to help after his daughter told him about the crash.

He said that as he neared the crash site, the scale of the accident became clear when he saw one carriage wedged inside another and scores of bodies.

"Just imagine what was inside," he said.

The pharmacist said he brought first-aid materials, painkillers, and tranquillisers from his pharmacy, as well as blankets, to help treat the injured.

He also described how one passenger who had lost an arm in the crash was calmly asking for an ambulance, while another was saying his final goodbyes to his family.

"His last words were 'God is good'. For those of us who are believers, these are very beautiful words," Mr Garcia said.

Other locals brought bottles of water to give to passengers who were evacuated from the two trains.

Construction worker David Gómez was also working nearby when he heard the crash and ran to help, he told the newspaper El País.

"People were trying to get out through the windows … We cut through some fences to access the area and treated people with the first-aid kits we had brought until emergency services arrived," he said.

"As I was trying to pull a young woman out, there was a piece of a leg."

A visibly shaken Manuel Ortiz, who lives in Urda told AFP he had been transporting survivors all morning in his car.

The 49-year-old described a "horrific, horrible" scene that "smelled of an accident, of metal".

Ambulances and medical helicopters made trips to and from the site, while buses took survivors who were unharmed. A military emergency brigade was deployed to help.

Australian Education Minister Jason Clare said the Department of Foreign Affairs and Trade (DFAT) was not aware of any Australians who had been affected by the crash.

"As you'd expect, we've got consular officials in Spain who stand ready to help any Australians or any Australian families if they are affected," he told the ABC.

"I think the whole country is in shock at the moment, seeing these images on our screens. [They're] just horrific."

In a statement, DFAT offered its condolences to victims' families and other people affected by the collision.

Passengers' moments of chaos

Samy Paul, a British tourist, was aboard the train at the time of the crash and described the shock of the impact to The Associated Press after being rescued from the RENFE train.

"Suddenly, everything started falling apart. Bang! We fell down," he said.

"We realised carriage two, carriage one, all gone, all smashed. There was blood all over."

Passenger Ignacio Relaño was also travelling on the RENFE train. He told state broadcaster TVE the train stopped momentarily on the line, then started again and crashed into the IRYO train.

"We all felt the train abruptly slowing down and then the impact," he said.

"The car leaned to one side like it was about to tip over. I hit my nose, everything went flying, luggage, cell phones. Everything shook."

Pablo Mejia, 42, told AFP he had miraculously survived with injuries to his head after changing his seat.

With blood staining his grey jumper, he recounted "a very strong hit".

"It lasted a long time until it stopped, lots of people on the floor, on top of each other, seats ripped out, suitcases, a lot of chaos," he said.

'Devastating' search for family members

A few hours after the crash, Urda was filled with police, firefighters and emergency workers from across the region, and the local sports hall was converted into a centre for survivors.

The local primary school was reserved for relatives of the victims, where a volunteer psychologist from Madrid called Carmen said she had been helping out since the morning.

"There were many mothers who found out their children had been killed," she said.

"That was the worst of today. Telling a mother that her child has died in a train crash is devastating."

Some relatives made the two-hour trip from Madrid, the Spanish capital, to search for family members.

A woman who gave her name as Ana said she travelled to Urda after environmental police called to say they had found their dog, Trece, who was on board a train with her husband, Pepe.

Ana fought back tears as she described searching for her husband at the crash site, Urda's sports hall and the primary school, adding that his name was not on any list.

Rescue workers continue to scour the wreckage of the two trains in search of survivors and bodies of victims.

The collision is the deadliest in Europe since a 2013 crash in Spain's Santiago de Compostela left 80 people dead.

Spanish Prime Minister Pedro Sánchez has declared three days of national mourning and called for increased safety measures to restore confidence in the country's high-speed rail system.

ABC/Wires