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 reported that 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 commented on X.

A construction worker told Reuters that he was pumping concrete into the building's lower floors when the collapse occurred, prompting him to flee after witnessing a large cloud of dust.

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

Rehbilita, the development company, indicated that the building was undergoing comprehensive renovation to operate as a four-star hotel.