A helicopter was also deployed, the department tweeted. Photos of the aftermath showed a collapsed roof and blackened and gutted interiors.
The cause of the fire was not immediately clear, and authorities are investigating.
Diego Seral, a spokesman for the national police, told reporters that the fire started at the Fonda Milagros nightclub — one of three adjoining clubs — and that it sustained most of the damage, according to Reuters.
In a news conference Monday, local officials said two of the three nightclubs were ordered to close a year ago after they were found to lack valid permits. Teatre, one of the clubs, had split its operations into two and requested a special permit, which it did not receive. It was ordered to close in October 2022, the local officials said, adding that the city of Murcia will join a pending lawsuit against the club.
Antonio Navarro, the local official in charge of urban planning, said it was unclear whether inspectors had visited recently to make sure the order was enforced.
“We are going to hold anyone who might have been responsible to account,” he told reporters.
In a post on its Instagram page, the nightclub described the incident as “tragic” and said it was cooperating with authorities to determine the cause of the blaze.
On Sunday, dazed relatives and friends waited outside the building for information on the missing.
One witness, who said his friends were still unaccounted for, told Reuters that he left moments before the fire alarm went off and the lights went out.
Three of the dead had been identified as of Sunday evening, Ballesta said at a news conference, and DNA tests are being conducted to identify the others.
Spanish Prime Minister Pedro Sánchez expressed “solidarity with the victims and relatives of the tragic fire” and offered assistance to local authorities.
In 1990, at least 43 people were killed when a blaze engulfed a basement disco in Zaragoza, in northeastern Spain.