At least 13 people have died in a fire at a nightclub in the south-eastern city of Murcia.
The blaze broke out in the Fonda Milagros nightclub in the Atalayas area, at around 06:00 local time (04:00 GMT).
Video shared online showed flames raging above the building and thick, dark smoke pouring out of its windows.
Emergency services are looking for people who are missing and were in the premises at the time.
They have warned the number of victims could still rise.
Diego Seral, of the national police, told Spanish TV channel RTE that at the whereabouts of 15 people were still unknown. He had earlier said "substantial structural damage" caused the collapse of the nightclub.
A 28-year-old woman who has not been found sent a voice note to her mother when the fire had started, according to the La Verdad de Murcia newspaper, saying: "Mummy, I love you, we're going to die."
She had gone out with her partner and some friends from the nearby town of Caravaca de la Cruz.
"They went because in Caravaca there are no nightclubs," the woman's father, named as Jairo, told the paper. "It was the second time she had been."
Firefighters finally managed to enter the building at around 08:00 and discovered four bodies, then two others around 40 minutes later. They continued to find bodies as they searched the Fonda Milagros premises.
Four people are being treated in hospital for smoke inhalation, and a local sports venue is being used to provide counselling for those affected.
It is not clear what caused the fire, which broke out when the club was still busy.
Among the victims identified so far, many were attending a birthday party, La Verdad de Murcia reported. They reported that one of the partygoers - who was there with his cousins, and his aunt, said he returned home amid the confusion after the flames broke out, but when he got there - was told his family had not left the building.
It was not clear if they were amongst those confirmed dead.
Murcia town hall said it deeply regretted the accident and offered condolences to those affected.
"We are devastated," Murcia Mayor Jose Ballesta said on Spanish TV channel 24h, adding rescuers were still searching for several people reported missing.
He has decreed three days of mourning in Murcia.
Relatives are arriving at the scene to try to locate loved ones, he added.
This is believed to be the worst nightclub fire in more than 30 years. In 1990, 43 people were killed in a blaze in a venue in Zaragoza.
Source: BBC
