At least three people were killed on Wednesday when a huge explosion ripped through a building in Madrid, with officials confirming it was caused by a gas leak.

Images from the scene showed the walls on the top four or five storeys of the residential building in the heart of the La Latina neighbourhood had been blown out, with debris littered far and wide.

The cause of the blast was said to be a gas explosion
The cause of the blast was said to be a gas explosion AFP / GABRIEL BOUYS

Government representative Jose Manuel Franco told Spain's public television that the blast occurred as a team of workmen were repairing the building's boiler.

Images broadcast on Spanish television showed cars destroyed by the force of the explosion and smoke billowing from the top floor of the six-storey building which housed local priests.

"I was just leaving a nearby clinic when I heard a very big explosion, it was so big I thought it was a bomb," Valentin Moreno, a 48-year-old salesman told AFP.

Emergency personnel secure the area surrounding a building damaged in an explosion in Madrid
Emergency personnel secure the area surrounding a building damaged in an explosion in Madrid AFP / GABRIEL BOUYS

"There were people running and a lot of smoke and when I got there, I saw the building's facade had been completely destroyed."

Franco confirmed it was a "gas explosion" and said there were three people dead and one missing, indicationg the toll could rise further.

At least one person sustained serious injuries, although no-one was hurt in a neighbouring elderly care home, he added.

Madrid emergency services rush to the site of a strong explosion in Madrid that has killed at least two people
Madrid emergency services rush to the site of a strong explosion in Madrid that has killed at least two people AFPTV / Rebeca MAYORGA

Hundreds of police and rescuers filled the streets around the building which the archdiocese said housed local priests who worked in the area.

"Please pray there are no victims," tweeted the Virgin de la Paloma parish church, saying "one lay person has not been found".

"These were the living quarters for the local parish priests. They are being treated by the ambulance crews and out of danger," it said.

Map of Madrid locating a multi-storey building which hit by a deadly explosion on Wednesday.
Map of Madrid locating a multi-storey building which hit by a deadly explosion on Wednesday. AFP / Patricio ARANA

The building is located next door to an elderly care home, but no-one there was hurt, the head of the residence told Spanish public television.

"There are no injuries among staff or residents. There were just over 100 people inside at the time," said Antonio Berlanga, director of the four-storey Los Nogales La Paloma residence.

Nine fire crews and 11 ambulances were dispatched to the scene with hundreds of police and rescuers filling the street, which was completely closed off to traffic and pedestrians, AFP correspondents said.

"Unfortunately we are mourning the death of several people in the explosion on Calle Toledo," tweeted Spanish Prime Minister Pedro Sanchez, offering his condolences to the families of the dead and the injured.

Lola Lopez Bravo was having lunch with her six-year-old son in their nearby home when the blast occurred, bringing down the wall in her apartment.

"We were eating, suddenly we heard a noise and the wall in front of us started falling on top of us," the 44-year-old told AFP.

"There was a huge hole in the wall and then the rubble started falling so we ran out of the house and went to a neighbour's place."

Lorenzo Fomento, a 43-year-old Italian salesman who was working from home at a nearby apartment, told AFP the noise was tremendous.

"I never heard something as loud before."

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