Local authorities failed to carry out regular fire and safety inspections at the bar in Crans-Montana, Switzerland, Mayor Nicolas Féraud admitted.
The bar has not been inspected once in the last five years, the BBC reports.
"We bitterly regret that," Féraud said at a press conference.
"We are extremely saddened by this and I know how difficult this will be for the families."
In addition to the fatalities, a total of 116 people were injured in the fire. Authorities believe the fire was started by burning ice torches inserted into champagne bottles that were held too close to the ceiling. Pyrotechnics are now banned in bars and restaurants in Switzerland, authorities announced at the press conference.
The bar's two owners are suspected of, among other things, causing the death of another person.
