At least three people were killed when an explosion ripped through a building in central Madrid, the city’s emergency information office said in a tweet on Wednesday.
A further eight people were injured in the blast on Calle de Toledo, one seriously, he added.
Madrid Mayor Jose Luis Martinez Almeida told reporters at the scene that initial investigations indicated that the explosion was caused by a gas leak.
According to Manuel Spanish representative of the Spanish government, a technician who worked on the boiler is missing.
The general secretary of Madrid, Avelino Sevilla, told Spain’s TVE that one person linked to the Catholic Church who occupies part of the building is still missing.
The blast significantly damaged the six-story building, the images and footage posted by the city’s emergency services on social media.
The top five floors were completely destroyed, with walls blown out, while the bottom two floors were still intact, but in places were charred from the flames. Debris and dust cover the immediate vicinity of the building.
Emergency teams can be seen helping several people on the ground.
Witnesses told Reuters a plume of smoke could be seen after the blast hit at least four floors of the building, emergency services tweeted.
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Leire Reparaz, who lives in the area, told the Associated Press she heard a loud explosion shortly before 3pm local time (9am ET).
“We did not know where the sound was coming 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 smoke a lot of gray.”
Reuters contributed to this report.