The explosion destroyed a building located in the city center and left "at least" two dead according to the mayor of Madrid.
Six floors of the building were blown away by the explosion, which was apparently caused by gas.
A very violent explosion apparently caused by gas destroyed a building in central Madrid on Wednesday, leaving "at least" two dead and an unspecified number injured, according to the mayor of the Spanish capital.
"It seems that there was a gas explosion," José Luiz Martínez Almeida told reporters near the site of the explosion, reporting "preliminary" information.
The explosion, the violence of which all witnesses pointed out, destroyed a building located at 98 rue de Tolède, in the city center.
Six floors blown away by the explosion
"I have never heard such a loud noise," Lorenzo Fomento, 43, an Italian salesman working in the neighborhood told AFP.
Six floors of the building were blown away by the explosion, according to one of the AFP correspondents on the spot.
The building, from which smoke was escaping and the facade of which was destroyed, adjoins a residence for the elderly and is close to a school.
Firefighters and emergency services quickly arrived and began to evacuate the occupants of the retirement home, as police cordoned off the street.
The mayor of Madrid said that no occupant of the retirement home was injured.
A large rescue tent was hastily set up near the site of the explosion.