At least three people died when an explosion hit a building in central Madrid, the city’s Emergency Information Office said in a tweet on Wednesday.
Another eight people were injured in the explosion on Calle de Toledo, one seriously, he added.
Madrid Mayor Jose Luis Martinez Almeida told reporters at the scene that initial investigations suggested the explosion was caused by a gas leak.
A technician who worked on the boiler is missing, according to the Spanish government representative for the Madrid region, said José Manuel Franco.
Madrid’s vicar general, Avelino Sevilla, told TVE Spain that a person linked to the Catholic Church that occupies part of the building is still missing.
The blast caused substantial damage to the six-story building, according to images and images posted on social media by the city’s emergency services.
The top five floors were completely destroyed, with the walls blown up, while the bottom two floors were still almost intact, but charred in places by the flames. Debris and dust covered the building’s surroundings.
Emergency teams can be seen helping several people on the ground.
Witnesses told Reuters that a plume of smoke could be seen after the explosion that affected at least four floors of the building, tweeted the Emergency Information Office.
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Leire Reparaz, who lives in the area, told the Associated Press that she heard a strong explosion just before 3 pm local time (9 am ET).
“We didn’t know where the sound came from,” said Reparaz, 24. “We went up the stairs to the top of our building and we could see the structure of the building and a lot of gray smoke.”
Reuters contributed to this report.