The death toll from a fire at an apartment block in the eastern Spanish city of Valencia has risen to 10.

The bodies were found in the first police inspection of the gutted residential buildings, according to Pilar Bernabe, the national government delegate in Valencia.

She said the bodies matched with the list of 10 people that authorities had deemed missing.

Spanish National Television and private news agency Europa Press reported that four people who had initially been included in the missing list of 14 had been located alive by authorities.

Meanwhile, questions abounded as to how the fire spread so rapidly.

Experts suggested that a type of cladding might have made the blaze spread faster, but Valencia mayor Maraa Jose Catala said the cause of the fire was still not known and it was too early to comment on whether some materials used in construction of the modern complex might have contributed.

The fire started on Thursday evening and quickly engulfed the buildings.

Neighbours on Friday described seeing the rapid spread of the blaze, residents stuck on balconies and hearing children screaming.

“I have no words to describe the suffering of those poor people,” said Sara Plaza.

Alejandra Alarcon said that it took 15 minutes for the fire to engulf the entire building.

She added that she heard children screaming and explosions.

Experts said that the building’s cladding may have been to blame for the fire’s ferocity.

The vice-president of the Valencia College of Industrial and Technical Engineers, Esther Puchades, who once inspected the building, told state news agency Efe that the cladding used included polyurethane and when “heated it is like plastic and it ignites”.

She said it was the first fire of its type in Spain, but that other blazes involving the material have been similarly destructive in the UK and China.

IPUR, Spain’s polyurethane manufacturers’ association, issued a statement contesting Ms Puchades’ claim, saying there was no evidence that polyurethane was used in the Valencia building’s facade.

The June 2017 fire at Grenfell Tower in London, which had similar cladding, caused 72 deaths.

Fifteen people were treated for injuries and two remained in hospital. Both were said to be stable.

Prime Minister Pedro Sanchez visited the scene, promising support for those affected and expressing gratitude to firefighters and military personnel who worked to extinguish the blaze.

Pope Francis also sent a telegram of condolences.

It was not immediately known how many people were in the two buildings when the fire broke out, but dozens are believed to have lost their homes and belongings. The complex had some 140 apartments.

The Valencia regional government declared three days of mourning and announced financial aid to cover accommodation, clothing and food.

Weekend football games involving Valencia and Levante have been postponed after both clubs requested not to play in the immediate aftermath of the fire, the Spanish league said.

Residents were housed overnight in hotels or in the homes of relatives and neighbours, authorities said. Neighbours also responded by donating clothes and food in shops for the survivors.

Firefighters rushed to the scene on the outskirts of the city as flames burst from windows. They used a crane to lift two residents from one of the balconies.

Some 90 soldiers from Spain’s Military Emergency Unit and 40 firefighting trucks also were deployed.

The fire sent clouds of black smoke billowing skywards that could be seen from miles away. Spain’s weather agency, Aemet, reported winds of up to 40mph at the time.