Police said the victims were a Spanish man, two German women and a Senegalese man, reported to be Abdoulaye Diop, who made national headlines in 2017 for rescuing a man who was struggling in waters off the Majorca coast.

Part of the Medusa Beach Club, a beachside restaurant in one of the busiest areas of the regional capital Palma de Mallorca, collapsed at about 20:30 local time (19:30 BST) on Thursday night.

People fell into the basement below, where there were customers and staff.

Police say the terrace caved in because of “excessive weight” being placed on it. Local media reported that Investigators were looking into whether the building complied with regulations.

Dutch tourists Wessel Roos, 21, and his girlfriend Madelin Muijs, 20, were eating at a grill just a few metres away from the Medusa restaurant when the collapse happened.

“Suddenly we heard an explosion. It was not a big boom, but we just knew something was up. You could also feel the vibration of the ceiling falling down,” Mr Roos told the BBC.

“It was chaos and there were people screaming.

“I was looking at what happened and thought someone had been murdered by a shooter.

“Then I saw the ceiling was not there any more, it had fallen on the ground and the ground floor was also broken.”

One firefighter described the scene as “nightmarish” to local newspaper Ultima Hora. He added that when his team arrived, people were crying and screaming as they stood around the rubble on the floor.

Raúl Pursnami, owner of fashion store Moda Meena on Cartago Street, next to the restaurant, said he saw the disaster unfold.

“I can hardly even speak. There were people eating, they were on vacation and now look what happened,” he told El País.

Santiago Aranga was walking his dog across the street when he heard a “boom” that sounded “like a bomb”.

“There was screaming, crying, hysterics,” he told local television station Trece.

Most people in the area were German tourists. “It was very difficult to try to calm them down, to pull people out in another language. I don’t understand or speak German,” he added.

Diop, 44, had reportedly just left a nearby gym and was having his daily coffee at the restaurant when it collapsed, his friends told local media.

In 2017, he earned national praise for rescuing a man who had entered the water in Playa de Palma and was having trouble returning to shore.

At the time, he told local paper Ultima Hora: “It was two degrees and the water was freezing, but when you see a person in that situation you act without thinking to save their life.”

One man was pulled from the rubble with a broken arm.

The Medusa Beach Club is one of dozens of bars, restaurants and hotels located just off Playa de Palma, a long beach stretching eastwards from the city of Palma, which cater to tourists who stay in the area. It is particularly popular with German tourists.

Officials say that psychology experts would be brought to the scene to aid those traumatised by the incident.

After the collapse, Mr Roos and his girlfriend returned to their hotel and prayed that those involved would survive, he said.

“It is a really weird feeling. When we had breakfast this morning and walked by, you can see blood on the brick there,” he said.

“[My girlfriend is] very shocked, she didn’t sleep well, she’s a little bit anxious. It was really difficult to see.”