The regional government of Madrid has thanked the public for donating blood in the aftermath of the deadly train crash on Wednesday.

It says in an update on social media that the Blood Transfusion Centre has received more than 4,000 donations at points across the region.

Image source, Elizabeth Conway / BBC

Cesar Vicente tells news agency APTN that his father is missing. He describes not knowing where he is as "hell".

"At least let them tell us about the people who are not identified, and at least we can start ruling out hospitals because we don't know anything," Vicente says.

"This is chaos," he says.

"I hope to find him, oh my lord. I don't want this to happen to anyone," Vicente says. "This is unbearable. This is hell."

At least 69 people have been killed after a high-speed train collided with another south of Madrid shorty before 09:00 on Tuesday.

Here's what to know:

Injuries: There are reportedly dozens of people who are injured. A local official in the Castilla-La Mancha region says that of the 112 people hospitalised, 50 are still in hospital and 60 have been discharged. Some in critical condition are beginning to improve, the official adds.

Victim identification: Police are urging relatives to come forward and provide DNA samples, as efforts continue to identify victims at the crash site. A spokesperson for Spain's Guardia Civil tells the BBC relatives should go to local centres to offer samples. More than 900 people have been deployed from multiple departments, the spokesperson said.

The two trains involved: The first train - Iryo 6076 - left Atocha station in Madrid. It was carrying 147 people and was travelling to Seville. The second train, Renfe's AVE 2080, carried 397 passengers and was also heading from Madrid to Seville.

Computer failure: Spain's transport minister has said that a computer failure led to the initial halting of six trains - which included the two that crashed. He has said that the control centre would take over in such situations.

Audio recordings: Spanish media has released audio showing that the driver of one train was given permission to proceed at normal speed by the control centre. However, it appears controllers were notified that the Iryo train was stationary on the tracks ahead. Read more about the exchange here.

A period of mourning declared: Spanish Prime Minister Pedro Sánchez has declared three days of national mourning. "We will get to the bottom of this, and if there has been any negligence, it will come to light," he said.

Paloma Prieto Del Valle
Reporting from the crash site

Image source, Reuters

Alberto Núñez Feijóo, Spain's opposition leader, has just arrived at the emergency co-ordination centre near the crash site in Urda.

A little earlier, the country's Interior Minister Fernando Grande Marlaska and President of Castilla La-Mancha Emiliano Garcia-Page visited.

Sarah Rainsford
Reporting from Toledo

We just spoke to a young woman outside the main hospital in Toledo, who still doesn’t know whether her mother survived the train crash.

In tears, she told me her father was badly hurt and has been operated on here, like many of the victims, but the last she knows of her mother is that she was given a "red" sticker at the scene - to show that her condition was serious.

Now her family are touring the hospitals here, looking for her and desperate for news.

Last night, protesters gathered outside the Spanish transport ministry demanding accountability over the train crash.

Image source, Reuters

Elsewhere, a memorial has been placed at Atocha station while flags have been placed at half-mast as Spain holds three days of mourning for victims of the train crash.

The president of Spain's Castilla-La Mancha region has called for people to give blood in the coming days. Separately, families who believe a relative may be a victim are being urged to provide DNA, as rescue teams work to identify the dead.

Image source, Reuters

Image source, EPA/Shutterstock

Image source, EPA/Shutterstock

Sarah Rainsford
Reporting from Toledo

The bodies of those killed in yesterday’s crash have been brought to the main forensics institute in Toledo, and this is where families have been giving DNA samples to help identify the dead.

We saw one family, distraught and hugging one another for comfort. They didn’t want to talk.

The institute itself is cordoned off, but we could see refrigerated trucks parked outside, a small red tent and military police, and funeral vehicles arriving.

Emergency teams have said the search for bodies at the crash site itself is over. But some families are still unsure whether their relatives are dead.

One man, looking for news of his father who was on one of the trains, has been writing on social media about searching hospitals in desperation. Not all the injured have been identified, so there is still hope.

But the wait for all caught up in this tragedy is agonising.

Rajini Vaidyanathan
Reporting from the crash site

As dawn broke here at the crash site, police drones and helicopters hovered above.

The two trains are still on the tracks, as the sun came up. Through the night emergency workers were here, continuing their efforts to pick through the wreckage.

They're trying to find DNA and other evidence which might help identify more of the victims on board. A police van with around a dozen sniffer dogs also drove past us.

Nearby in the town of Urda relatives are desperately waiting for news.

Image source, AFP via Getty Images

There are still many question marks over this train crash disaster - one of the worst in Europe's modern history - but this is what we know so far about what has happened.

There were more than 500 passengers travelling across the two trains. One, the Iryo 6076, left Madrid at 07:54 local time (06:54 GMT) carrying 147 passengers to Seville.

The other, Renfe's AVE 2080, was also heading to Seville. It departed Madrid at 08:00 local time with 397 passengers on board.

Just before 09:00 local time, the AVE train crashed into the rear of the Iryo train, which appears to have been stationary near Urda in Toledo. At least three carriages of the Iryo train fell down an embankment off the tracks, as did part of the AVE train.

According to Spain's Transport Minister Óscar Puente, a computer failure led to the initial halting of six trains - including the two which crashed.

Puente said that in the event of system failures "the control centre takes over", and that a decision apparently to allow trains to move again was made "under inexplicable circumstances".

Image source, Getty Images

A representative from the Spanish government has called for "accountability" following the rail disaster.

Domènec Ruiz Devesa tells the BBC's Today programme a little earlier this morning that the crash is "not necessarily connected to a general lack of investment" in the Spanish rail network.

Devesa says the crash is "very different" to another incident on the same train line earlier this year which killed more than 40 people.

He says the main hypothesis for the more recent crash is "first the failure of the electronic system and then a human mistake".

He adds that there needs to be a technical and policy review following the disaster.

Devesa says that first step is to care for the victims, the wounded and continue the emergency efforts.

"Even as we speak not all bodies have been recovered," he adds. "There are people who are still to be accounted for."

Image source, Europa Press via Getty Images

The president of Spain's Castilla-La Mancha region, Emiliano García-Page, has been speaking at a news conference alongside Spanish Prime Minister Pedro Sánchez.

He tells reporters that has been some positive news about some of the survivors in hospital.

He gives his sincere thanks to all the staff who have been involved and asks people in the coming days to give blood.

He adds that his thoughts are with the victims and "we [must] never forget we are confronted by a human tragedy".

Image source, Europa Press via Getty Images

Spanish Prime Minister Pedro Sánchez has said that assistance centres have been established in the immediate region following the train disaster.

He tells a news conference that psychological assistance is being provided for relatives of victims, the victims themselves and for anyone who was in the area of the accident yesterday.

Sánchez praises the "tremendous work" done by rescuers and says the Spanish government is working very hard to find out the causes of the incident.

Rajini Vaidyanathan and Paloma Prieto Del Valle
BBC News

Speaking to BBC News in the last few moments, a spokesperson from the Guardia Civil says they have deployed more then 900 people from different specialist departments.

The priority now is the process of identification. They don't know how long that is going to take.

The Guardia Civil urges those with missing family members to go to one of the local centres which have been set up to offer DNA samples to help with victim identification.

Asked if the death toll could rise, the spokesperson says they do not know yet whether that is likely and their main goal remains to identify the victims.

Image source, Reuters

Audio recordings published by Spanish news outlets, including El Pais and RTVE, reveal the conversations that took place between the two train's drivers and the control centre in the Spanish capital ahead of the crash.

In one recording, a control centre operator tells the Renfe driver to resume its journey at normal speed after some technical issues.

"Continue your journey and then proceed under [Lateral Signalling Block], at normal speed with normal operation," the control centre operator says to the driver.

The driver replies, "At normal speed?" To which the controller says: "Yes."

The Lateral Signaling Block is a back-up or alternative train system used when the automatic signalling or data transmission system fails.

Later, the driver of the other Iryo train says in another audio recording that communication with the train-control system has been lost and they are stationary at Urda.

The train "is stationary in front of the entry signal at Urda", the driver tells the control centre operator. After a series of exchanges, the driver is then told to "resume the journey" normally.

The Iryo driver then contacts the control centre again, according to a later recording, saying they cannot start the train. "The train won't allow me to control the [security] system. That's why I am still stopped in front of the entry signal," they say.

The latter recording suggests that the controller had been notified that the Iryo train remained stationary as the Renfe train approached.

Image source, EPA/Shutterstock

There's been a lot of focus on a control centre which Spain's Transport Minister Óscar Puente says typically takes charge of deciding when trains can move again in the event of system failures.

Spanish media has obtained audio recordings obtained between train controllers working for a rail infrastructure company in Adif in Madrid and the train drivers.

They appear to show that one high-speed train was given clearance to move at 08:36 even though another some 25km ahead had stalled.

One train, run by state-owned operator Renfe, had 397 passengers on board. Ahead of it on the same line was a train run by private operator Iryo, with 147 passengers.

A reported issue with the automatic signalling system - a computer failure - had forced all trains to halt on the affected stretch.

But later the Renfe train was ordered to proceed in "error", according to Spain's transport minister.

In our next post, we'll bring you details about what was said in the exchange.

Image source, Reuters

Audio recordings published in Spanish media reveal the conversations between train drivers and a railway control centre minutes before one of the worst rail disasters in Europe's modern history.

In one recording a control centre operator tells a train driver to "continue your journey... at normal speed with normal operation" following some technical issues.

The recordings come as Spain has entered three days of mourning. At least 68 people were killed and dozens more were injured when a train travelling from Madrid to Seville crashed into a second train that appears to have been stationary on Wednesday morning.

Emergency crews worked through the night to cut open metal carriages in the search for victims, with many of the crash victims still to be identified.

Spanish Prime Minister Pedro Sánchez has described how the "whole of Spain is grieving" following the disaster.

Hundreds of personnel have been deployed to the disaster site to help with recovery efforts, according to Spain's interior ministry, with drones and helicopters being used to find victims and remove rubble.

Sarah Rainsford
Eastern and Southern Europe correspondent, reporting from the crash site

More than 12 hours after the two trains collided here near Urda, and well after nightfall, the massive recovery operation is still in full swing.

There are powerful lights at the scene, illuminating several train carriages tilting dangerously to one side on the tracks.

I can make out some of the wreckage of other carriages, cascading down the embankment. Among it all are the emergency workers, confronting the horror of Europe’s worst rail disaster in many years.

The occasional drone takes off to survey the scene, shining bright beams down below, and there’s the non-stop clunk and thud of metal as giant cranes and cutters go to work in the ruins, perhaps checking for more victims.

At one point a funeral van passed us on the road.

As families with missing relatives wait, and forensic teams in Toledo work to identify dozens of people who were killed here, Spaniards all over the country are asking tough questions about how this disaster was possible.

We're ending our live coverage here, but you can read more in the news story.

Image source, Reuters

At least 68 people have been killed and dozens more injured in Spain after a high-speed train collided with another train just south of the capital Madrid.

More than 500 passengers were travelling on the two trains at the time - this graphic shows how the crash unfolded.

"Suitcases started flying, people started screaming," a survivor tells the BBC, saying they don't think they will ever recover from witnessing the horrific aftermath.

Transport Minister Óscar Puente says a computer failure led to the initial halting of six trains, including the two trains that subsequently collided.

"In the event of a system failure, the control centre takes over," Puente says, adding it was the control centre which decided to allow the trains to move again, without any speed restrictions.

That decision, he says, was made "under inexplicable circumstances".

Protesters have gathered outside the transport ministry, and one of the country's largest trade unions has called on Puente to resign.

Prime Minister Pedro Sánchez says "the whole of Spain is grieving", adding: "We will get to the bottom of this, and if there has been any negligence, it will come to light."

Image source, Reuters

Today's incident, which has killed at least 68 people, is the second deadly train collision on the same line in less than a year and will likely raise questions over Spain's train infrastructure.

It is among the most deadly train, tram and subway crashes in Europe in recent years:

Greece, 2023: A passenger train from Athens to Thessaloniki smashed head-on into a goods train on the same line in northern Greece, killing 57 people.

Spain, 2013: A railway accident left 80 people dead and 145 injured when an eight-carriage high-speed train derailed and crashed near the north-western city of Santiago de Compostela.

Montenegro, 2006: At least 44 were killed and more than 180 injured when a passenger train plunged into a ravine outside the capital, Podgorica.

Austria, 2000: A cable car on a funicular train caught fire in a mountain tunnel high above the town of Kaprun, killing 155 people.

Germany, 1998: A high-speed train derailed in Eschede in Lower Saxony, killing 101 people, in what was the country's deadliest post-war rail disaster.

People in the regional centre of Toledo held a minute's silence at 20:00 local time (19:00 GMT) for the victims of today's train crash.

Local leader Emiliano García-Page and Education Minister Milagros Tolon were among those taking part in the vigil.

Image source, Europa Press via Getty Images