At least 40 people were killed on Wednesday in a high-speed collision near Toledo in central Spain, Spanish Civil Protection sources told national media.
The two trains were carrying more than 540 people on the line from Madrid to Seville.
Esther Padilla, spokeswoman for the Castilla-La Mancha region, said the latest confirmed figure was 10 dead but that the number of casualties was likely to rise.
“Very likely we will be talking about a higher number,” Ms Padilla said, adding that several carriages had plunged down an embankment.
A Renfe and an Iryo train crashed just after 9am local time, causing two Iryo wagons to derail.
The collision comes nine months after an accident between high-speed trains belonging to the same operators on the same line that killed 46 people.
Miguel, a passenger travelling with several colleagues in the rear car of one of the trains, described to Cope radio the moment of the accident.
“We heard a massive roar, a truly enormous thud that went on for 10 seconds, as if the train were about to derail. Through the right-hand window, we could see a wrecked train – I imagine it must have been the other one,” he said.
Spanish Prime Minister Pedro Sanchez said he was shocked by the accident and remained in contact with Transport Minister Oscar Puente and the president of Castilla-La Mancha, Emiliano Garcia-Page.
Solidarity
Emergency services were working at the scene to assist those affected and ensure their safety, Mr Sanchez said, adding that the response was being co-ordinated with all the administrations involved.
“My affection, solidarity and support go to all the victims and their families,” he wrote on X.
Footage by regional Castilla La Mancha Television showed a derailed train with at least one carriage remaining on an elevated section of track while twisted metal, broken panels and wreckage could be seen strewn across an embankment beneath the line.
Manuel Galan, mayor of nearby town of Urda, told Cadena SER that emergency services had asked the town council to prepare emergency facilities, including a sports hall, to accommodate passengers and the injured.
The collision comes nine months after an accident between high-speed trains belonging to the same operators on the same line that killed 46 people.
That crash in January, which occurred after a train derailed and smashed into an oncoming train near Adamuz, in Cordoba province, triggered a debate about the level of investment in railway maintenance in recent years.
