At least 59 people died and around 155 were injured after a fire tore through a nightclub in North Macedonia, with the country’s interior minister blaming pyrotechnics.

Hundreds had gathered at the ‘Pulse’ nightclub in the town of Kochani, east of the capital Skopje, to watch local act DNK perform when the blaze broke out in the early hours of Sunday morning. The music duo are reported to be among those killed.

The ages of the victims range from 16 to 24, the head of Kochani General Hospital, Dr. Kristina Serafimova, said, according to state media outlet MIA. The majority of those who died were trampled in the crowd crush, she added.

Interior Minister Panche Toshkovski announced the number of deaths at a press conference on Sunday, saying on stage effects triggered a blaze that quickly spread.

“The fire was caused by pyrotechnics used for lighting effects at the concert and activated the sprinklers,” he said. “Most likely, sparks caught a part of the ceiling that was made of flammable material, causing the fire to spread to the entire discotheque in a short period of time, creating thick smoke.”

Video from inside the venue shows a band performing as pyrotechnic devices shoot out sparks at the front of the stage.

One concert-goer, 22-year-old Marija Taseva, told local television channel Kanal 5 that as she tried to escape the blaze, she fell to the ground and people trampled over her .

“Everyone was trying to save themselves,” Taseva said, adding that she lost contact with her sister in the chaos. “We can’t find her in any hospital,” she said.

At least 152 people who were injured in the tragedy were taken to hospitals across the country, MIA reported, citing the country’s health ministry. Dozens of victims are being treated for second-degree burns on their hands and faces, Vlatko Zahariev, head of the city of Shtip’s hospital said, according to MIA.

Twenty-seven of the most seriously injured victims will receive treatment abroad, the health ministry said, according to MIA.

Football player Andrej Lazarov was confirmed to be among the deceased, his club FC Shkupi announced in an Instagram post Sunday. Lazarov was 25.

Police detained the owner of the nightclub on Sunday morning, MIA reported, as the country’s Justice Minister, Igor Filkov, said that all those involved in the tragedy will be held responsible. Four people are wanted by police in connection to the disaster.

North Macedonian Prime Minister Hristijan Mickoski said it was a “difficult and very sad day.”

“The loss of so many young lives is irreparable, while the pain of our families, our close ones and our friends is immeasurable,” he wrote on X.

Leaders from across Europe have taken to social media to express their condolences for the disaster, including Ursula von der Leyen, President of the European Commission, and Antonio Costa, President of the European Council.

Angela Aggeler, the US ambassador to North Macedonia, also posted about the incident on X, writing that her “heart breaks” for the victims of the tragedy and offering the US embassy’s assistance and resources.

Pope Francis also expressed his “deep” condolences to the families of the victims, assuring them in a telegram sent on his behalf that those who lost their lives will be remembered in prayer.

The disaster is one of the deadliest nightclub fires to have taken place in at least a decade. In 2015, a crowded nightclub in Bucharest, Romania was engulfed in flames after pyrotechnics were set off during a concert, killing 64 people.

Two years earlier, more than 240 people died after a fire broke out at a nightclub in Santa Maria, Brazil. Pyrotechnics were also being used inside the club when the fire started.

North Macedonia’s government is set to declare a week of national mourning in the wake of Sunday’s tragedy.