At least four people were killed in a fire that engulfed an apartment building in Valencia in eastern Spain, local authorities said on Friday, while at least 19 people remained missing.

Television footage showed the entire facade of the building ablaze as burning segments fell to the pavement below and small explosions were heard inside.

Local media reported several residents calling for help from the balconies of their apartments.

The fire began on the fourth floor of the building in an affluent neighbourhood of Spain's third-largest city and spread to other apartments, emergency services said on X.

Ana Mari Gonzalez, who works in a nearby clinic, told state broadcaster TVE she could see firefighters working to rescue a teenage boy trapped on the building's first floor.

Sixteen firefighting units and five ambulances were deployed at the scene, according to local emergency services. Rescue teams said 19 people were missing.

The deputy head of emergency services in the Valencia region, Jorge Suarez, told reporters that four people had been confirmed dead in the blaze, adding that the building's characteristics did not allow to extinguish the flames inside, with firefighters first attempting to cool down the facade.

Suarez said that there did not appear to be a risk of the structure collapsing for now, but firefighters were nonetheless operating from the outside due to security criteria. (Reporting by Antoine Demaison, Marco Trujillo and Eva Manez; Writing by David Latona; Editing by William Maclean)