Spain's second high-speed rail disaster this year, in which one train struck another from behind, killing 69 people, has raised fresh concerns about the safety of the country's rail network ahead of a national election.

Search teams with sniffer dogs continued to look for victims on Thursday morning, a day after the collision in central Spain. Cranes helped shift the carriages as police and soldiers helped pick through the wreckage strewn down the gravel slope where at least three train carriages were tossed by the impact.

Officials have said the death toll was provisional. One more body was found overnight, taking the death toll to 69, according to the regional leader of Castilla La Mancha, Emiliano García-Page.

"Yesterday we experienced a catastrophe that without a doubt has left all of Spain in shock," García-Page said.

García-Page said that a crane would lift a damaged carriage that had flipped over. He added that 50 people remained hospitalized. "Besides bodies, there are body parts that need to be identified," García-Page said. Spain's government declared three days of mourning starting Thursday.

Global Affairs Canada (GAC) told CBC News on Wednesday that it is aware of six Canadians who were injured in the crash, and a seventh person was unaccounted for. The severity of injuries was not clear, with the department citing privacy considerations.

"Our thoughts are with their families and loved ones as well as all of those affected," the GAC statement said. "Canadian officials are providing consular assistance and are in contact with local authorities to gather more information." Calls for transport minister to resign Spain's high-speed rail network has been considered one of the nation's crowning achievements. It is the world's second-largest, after China's. Until this year, it had not endured a deadly crash since coming into service more than three decades ago.

Forty-six people died in a January crash when one train jumped the track and slammed into the side of another going the opposite way in southern Spain.

Both deadly crashes this year took place on the same rail line. Each involved a train operated by state-owned RENFE and another operated by privately owned IRYO. Spain liberalized its high-speed rail service in 2021, with the Italian IRYO starting service the following year.

Transport Minister Óscar Puente faced media questions over whether he would resign following a second major train wreck under his watch. He said he was fully focused on dealing with the collision, not his future.

Puente said that the crash was caused by what he called the "inexplicable" order from a central command centre for Spain's trains after a security system had failed. He said the train engineers were not to blame.

Puente said that at 8:30 a.m. local time the security system on a stretch of 63 kilometres stopped working due to a computer malfunction, causing all trains on that stretch to stop. At that point the IRYO train was stopped near the town of Urda, while the RENFE train was 25 kilometres behind it.

But a few minutes later the central command told the RENFE train to start running again without any speed restrictions, and it ended up colliding with the stationary IRYO train at 8:53 a.m.

Puente said that the train should never have been told to start moving again since there was still a "stop signal" active on that line. And if it had, at least it should have been told to go at reduced speed.

Thousands of travellers were left stranded and searching for alternative transport after the high-speed line connecting Madrid and Seville was shut down.

Crash becomes another issue on campaign trail The collision Wednesday morning that turned a sleepy stretch of rail lined by olive groves into a scene of carnage came just four weeks before the country votes in a national election.

Spanish Prime Minister Pedro Sánchez visited the crash site in the province of Toledo on Wednesday. He pledged an investigation into the latest collision and improvements to prevent another tragedy.

"It is clear that we need to reinforce the safety of our train service to rebuild the trust in our high-speed rail," Sánchez said. "It is not acceptable for a country like Spain to endure two high-speed train accidents in the same year." How did Spain's housing crisis get so bad it forced the PM to call a snap election?

Spanish pensioner Maricarmen, symbol of country's housing crisis, dead at 87 Sánchez has weathered many crises since taking power in 2018, but polls show he and his Socialists faces another uphill battle when voters cast ballots in Spain's first national election in more than three years, on Nov. 29.

Discontent over housing costs and high rents led to the early election call. Sánchez now also faces questions about the safety of Spain's rail service along with criticism from right-wing parties of his liberal migration policies and accusations of corruption against his party and his wife, which both he and his wife deny.

Sánchez's main rival, People's Party Leader Alberto Núñez Feijóo, demanded a full investigation of the crash on Wednesday. The conservative leader said that in respect for the victims his party cancelled its campaign events for the day.

The far-right Vox leader, Santiago Abascal, who is likely hoping to enter a coalition government with the conservatives, did not show the same restraint.

"I promise to work tirelessly until this government, which is a criminal organization, is sitting in a courtroom to answer for its crimes," he said.