At least 13 people have died in a fire at a nightclub in the south-eastern city of Murcia, Spanish authorities say. The blaze broke out in the popular Teatre 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. 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 building. 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. Diego Seral, of the national police, said "substantial structural damage" caused the collapse of the nightclub. 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 and locate loved ones, he added. Spain's Prime Minister Pedro Sanchez also shared his condolences on X, the platform formerly known as Twitter. He said the federal government would support the Murcia government with their recovery effort. Murcia's regional President Fernando Lopez Miras declared the days of mourning would be extended across the region, and flags of public buildings would fly at half mast. Miras gave thanks for the "huge expressions of affection from all of Spain that we are receiving in the Murcia region with regard to this tragedy." 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. — BBC