A fire engulfed two residential buildings in the eastern Spanish city of Valencia on Thursday, killing four people and leaving 19 others missing hours after the blaze started, authorities said, according to AP.

The fire sent fleeing residents onto balconies where some were rescued by firefighters, officials said.

Firefighters rushed to the scene on the outskirts of the city center as flames burst from windows of the 14-story residential building where the blaze apparently started. Residents could be seen waiting for rescue on balconies, and firefighters used a crane to lift two residents from one of the balconies.

Valencia’s assistant emergency services director, Jorge Suárez told reporters that four people were confirmed dead and that some six hours hours after the blaze started firefighters were trying to cool down the outside of the building before attempting to go inside.

Soldiers from Spain’s Military Emergency Unit also were deployed and medics set up a large tent to tend to the injured on the scene.

The cause of the fire was not immediately known, but news reports said it might have spread rapidly owing to materials used in the building’s structure.

The fire sent clouds of black smoke billowing skyward that could be seen from afar. Spain’s weather agency, Aemet, reported winds of up to 60 kph (40 mph) at the time.

The fire began in the early evening and spread to an adjacent building, state news agency Efe reported. Emergency service reports said that besides the four people killed, at least 13 were injured, most with fractures, burns and smoke inhalation. The 13 included six firefighters.

It was not immediately clear how many people were in the buildings or how many were rescued.

Spanish Prime Minister Pedro Sánchez posted a tweet on the X platform saying he was “shocked by the terrible fire in a building in Valencia,” adding that he had offered the city “all the help that is necessary.”

“I want to convey my solidarity to all the people affected and recognition to all the emergency personnel already deployed at the scene,” Sánchez said.