At least 21 people have been killed after a crash involving high-speed trains in southern Spain, as authorities warn the death toll could rise overnight.

More than 30 are being treated for serious injuries in the hospital, Spain's transport minister Oscar Puente said.

The incident happened near the town of Adamuz, close to the city of Cordoba, when a high-speed train travelling from Malaga to Madrid derailed and crossed over onto another track, the rail network operator Adif said.

The derailed train then collided with an oncoming train, travelling from Madrid to Huelva. Andalusian emergency services said at least 73 people in total were injured in the collision.

The incident appeared to be "extremely strange", Puente added, because the train derailed on a straight stretch of track, which had been refurbished in May last year.

The official cause is not yet known. An investigation is not expected to determine what happened for at least a month.

Spain's Prime Minister, Pedro Sánchez, said the country will endure a "night of deep pain".

Iryo, a private rail company that operated the journey from Malaga, said around 300 passengers were on board the train that first derailed, while the other train – operated by Renfe – had around 100 passengers.

The mayor of Adamuz, Rafael Moreno, was among the first on the scene of the accident. He described it as like "a nightmare".

In a post on X, the Emergency Agency of Andalucía urged any crash survivors to post on social media that they are alive.

The twisted wreckage of the train made it difficult to recover survivors and bodies, rescue crews said.

Cordoba fire chief Francisco Carmona told Spanish public broadcaster RTVE: "We have even had to remove a dead person to be able to reach someone alive. It is hard, tricky work."

According to Adif, the crash happened about ten minutes after the train left Malaga at 18:40 local time (17:40 GMT). The company said it was setting up spaces for relatives of victims at Atocha, Seville, Cordoba, Malaga and Huelva stations.

All rail services between Madrid and Andalusia were suspended following the accident and will remain closed on Monday. The company said it will keep terminals open overnight for impacted passengers.

The type of train involved in the crash was a Freccia 1000, which can reach speeds of up to 400 km/h (250 mph), a spokesperson for the Italian rail company Ferrovie dello Stato told Reuters.

The Spanish Red Cross has deployed emergency support services to the scene and is also offering counselling to families nearby.

Miguel Ángel Rodríguez from the Red Cross told RNE radio: "The families are going through a situation of great anxiety due to the lack of information. These are very distressing moments."

Salvador Jimenez, a journalist with RTVE who was on one of the trains, said the impact felt like an "earthquake".

"I was in the first carriage. There was a moment when it felt like an earthquake and the train had indeed derailed," Jimenez said.

In his latest update on X, he said he was among a group of passengers waiting in the "freezing cold night" for buses to transport them to a local sports centre.

King Felipe VI and Queen Letizia said they were following news of the disaster with "with great concern".

"We extend our most heartfelt condolences to the relatives and loved ones of the dead, as well as our love and wishes for a swift recovery to the injured," the royal palace said on X.

French President Emmanuel Macron and European Commission chief Ursula von der Leyen have both offered condolences in statements.

"My thoughts are with the victims, their families and the entire Spanish people. France stands by your side," Macron wrote on social media.

In 2013, Spain suffered its worst high-speed train derailment in Galicia, north-west Spain, which left 80 people dead and 140 others injured.