Four people have died after a six-storey building, which was being refurbished partially, collapsed in the centre of the Spanish capital, Madrid.

The city's mayor, Jose Luis Martinez-Almeida, said the bodies of the last two of the people reported missing were recovered on Wednesday morning, some 15 hours after several floors at the property on Hileras Street collapsed.

Local media said the victims were a 30-year-old Spanish woman, who was managing the project, as well as three male workers from Mali, Guinea and Ecuador, aged between 30 and 50. Three other people were injured.

The former office block was being converted into a hotel. Authorities have launched an investigation.

Spanish emergency services said several crews - with drones and sniffer dogs - were deployed to look for those missing after Tuesday's collapse.

Two of the bodies were recovered on Tuesday night.

"All our love and support go to their families, friends, and colleagues in this very difficult time," Martinez-Almeida said in a post on X.

A construction worker told Reuters news agency he was pumping concrete into the building's lower floors outside when the building collapsed and ran away after seeing a large cloud of dust.

The building's façade remained intact despite the internal collapse.

According to the developer Rehbilita's website, the building was undergoing "comprehensive" renovation to operate as a four-star hotel.