'Extremely loud' explosion in Madrid city center left at least two people dead.

Iran Press/Europe: At least two people have died following an "extremely loud" explosion in the Spanish capital's city center - with rescue teams, firefighters and police sent to the scene.

Spanish media reports said the blast took place in a building near a nursing home and a school - and videos and images shared on social media showed rubble scattered in the street, Sky News reported.

The city's mayor confirmed there had been two deaths and said early information indicated the blast was likely caused by a gas leak.

Jose Luis Martínez-Almeida said there was an ongoing fire in the building devastated by the blast.

A witness told the AP news agency: "We didn't know where the sound came from. We all thought it was from the school.

"We went up the stairs to the top of our building and we could see the structure of the building and lots of grey smoke."

The nearby school was empty at the time, according to TVE, because classes had not resumed yet following a record snowfall in the Spanish capital on 9 January.