Spain's transport minister says he won't resign over the high-speed rail collision that has left at least 69 people dead.
Óscar Puente told a news conference in Madrid he had "nothing to hide" while repeating the government's vow to get to the bottom of the disaster, saying many questions needed to be answered.
"My duty right now is not to talk about whether I should remain in my position, but to resolve the problem," Puente said.
The transport minister has been facing calls to step down in the aftermath of the tragedy, including from political rivals, a trade union and demonstrators who protested outside the transport ministry on Wednesday night.
Dozens were killed and many more injured when a state-operated Renfe high-speed train smashed into the back of another stationary train operated by the Iryo company near the town of Urda, in the central Toledo province, on Wednesday morning.
A preliminary report released by transport investigators late on Thursday found the Renfe train was travelling between 160km/h (99.4mph) and 200km/h when the collision occurred, causing its front carriage to become embedded in the tail of the stationary train.
Spanish Prime Minister Pedro Sánchez said earlier on Friday that public trust in Spain's high-speed rail network had been broken and repeated it was "unacceptable" that there had been two similar tragedies within a year.
In January a collision on the same Madrid-Seville route killed 46 people in Adamuz in southern Spain.
Wednesday's tragedy was one of the worst rail disasters in Europe's modern history, and Spain's worst crash since 2013.
Puente said on Wednesday a computer failure at about 08:30 that morning led to the initial halt of six moving trains, including the two trains that subsequently collided.
Leaked audio recordings published in Spanish media revealed conversations between train drivers and a control centre just minutes before the crash.
Three audio recordings between Madrid's control centre and two train drivers appear to show that one high-speed train was given clearance to move even though another train had stalled on the track, about 25km (15 miles) ahead.
Puente had said that the decision to instruct the trains to move again, without any speed restrictions, was "inexplicable".
The leaking of the audio recordings has been criticised by some Spanish politicians, with Alberto Ibáñez, a member of Congress for the left-wing Sumar platform, writing on X that they were "despicable".
Meanwhile, Irene Montero - the prime ministerial candidate for the left-wing Podemos party - said responsibility for the crash should not be placed on one worker, adding that train drivers and experts have been warning against the liberalisation of the railway sector for years.
On Friday Puente said he was "not going to use any worker as a shield".
But he said "many questions" arose as a result of the tragedy and he wanted to look at them "one by one".
"If the investigation shows there is human error we will act in consequence of that," he said.
The country is observing three days of mourning, as the families of victims and the survivors of the crash struggle to comprehend how it could have happened.
The conservative People's Party joined calls for Puente's resignation after trade union CSIF called for the same earlier this week.
But Puente said on Friday he would not budge from his position.
"The easy thing for me would be to leave, but neither that fits with my character nor is it what the Prime Minister has asked me to do," he said.
"I feel immense pain and immense sadness for the victims and their relatives... I cannot let this pain paralyse me though. We have to find solutions to this problem."
