A teenager who ran back and forth to help survivors of a deadly high-speed rail crash in Spain has spoken of the 'terror' he witnessed at the scene.

Julio Rodriguez, 16, who has been dubbed 'the angel of Adamuz' by Spanish media, was among the first on the scene following a collision between two trains near the city of Córdoba, on Sunday evening.

One train had derailed and crossed over onto another track, before a second ploughed into the wreckage just moments later, at around 6.40pm local time.

Officials said the crash has claimed the lives of 42 people so far, with more than 120 injured. Thirty-nine people are still in hospital, including four children and 13 in intensive care.

Julio recalled that he was on his way home from a fishing trip with his mother and friend when they spotted two police cars and an ambulance rushing away in the distance. 

Curious as to what had happened, they followed the convoy and discovered the scene of the crash, which occurred close to the station in Cordoba province.

As he walked over to the carriages, which had slipped down a four-metre slope, Julio spoke to survivors and took down names and telephone numbers of relatives in the minutes before the rescuers arrived.

He also pulled a 10-year-old boy from the wrecked remains of one of the trains. 

'I didn't stop to think whether I was tired. I made the journey several times,' he told local media Sur.

His act of selflessness was recognised on Tuesday when King Felipe VI and Queen Letizia visited the scene of the crash and met with relatives of the victims, as well as the injured in hospital. 

The royal couple paid tribute to the teenager and spent time speaking with him about his experience.

They stood close to the train carriages, where a recovery operation is ongoing amid a three-day period of national mourning. 

Interior minister Fernando Grande-Marlaska revealed on Tuesday that 43 people are still missing since the crash occurred, with officials stating it could take several days yet before a final death toll can be confirmed.

After visiting the crash scene, the king and queen travelled to Cordoba, where they visited those recovering from their injuries in hospital, as well as families of the victims, The Times reported.

King Felipe said: 'No matter how good the infrastructure is, accidents happen. This one has been very tragic...It could have been much worse and the early response has minimised the number of fatalities.'

Among those affected by the crash was a six-year-old girl who lost her parents, brother and cousin. She was found walking barefoot along the track after escaping through a window.

Her parents were named on Monday as Jose Zamorano and shop owner Cristina Alvarez. They were killed alongside their 12-year-old son Pepe Zamorano and cousin Felix Zamorano. 

The family was returning from the Spanish capital after going to see the Lion King musical and watching Real Madrid beat LaLiga rivals Levante at the Santiago Bernabeu stadium. 

Remarkably, the young girl survived and needed only three stitches for a head wound. She is now recovering with her grandmother in a hotel in Cordoba following her ordeal. 

Sori Ruiz, who was close to Cristina, paid tribute in a statement and said: 'My deepest condolences to the family. May God give them comfort. This is a great loss for everyone.

'I was shocked by the news. Cristina was my classmate at school, and we spent many years together.

'May God rest her soul and give comfort to her family. I cannot imagine the pain felt by her family and loved ones.' 

Journalist Oscar Toro and his photojournalist wife Maria Clauss are also known to be among those who died in the train crash.

Jaime de Vicente Nunez, president of the Iberoamerican Cultural Association confirmed today on social media: 'Huelva is in mourning. Our Ibero-American Cultural Association is in mourning. 

'Maria Clauss and Oscar Toro, friends and members of our Association, great professionals and, above all, people of extraordinary human quality, have passed away.

'May they rest in peace and may we always remember their fruitful work and warm humanity.'

Friend Gabriel Cruz wrote in a tribute: 'Incredulous and stunned. A tragedy that devastates us. Deep sorrow for the victims and their families, for the friend who is gone. 

'Oscar Toro and María Claus were travelling on that train. With them, a little piece of ourselves is gone. Kind and generous people.

'I was fortunate to share many moments of friendship and camaraderie with Oscar, both in his role as President of the Huelva Journalists' Association and as a councillor in the socialist group. Also outside the workplace.

'All my love to the families of the victims. A kiss for María and Oscar.'

The cause of the crash is still being investigated, though some experts have pointed to the discovery of a broken rail joint on the tracks, which may have caused the initial derailment.