KOCANI, North Macedonia (AP) — A massive fire tore through an overcrowded nightclub in North Macedonia on Sunday, killing 59 people and injuring 155 in a chaotic escape during a live concert. The tragedy focused national attention on corruption in the small Balkan country as authorities detained 15 people.

The death toll may rise further, with 20 of the injured remain in critical condition, according to Health Minister Arben Taravari. The government has declared seven days of national mourning.

The pre-dawn blaze in the eastern town of Kocani left mostly young people dead and injured due to burns, smoke inhalation and a stampede in the desperate effort to reach the building’s single exit, officials said. People as young as 16 were among the casualties, they said.

Videos showed sparkling pyrotechnics on the stage hitting the ceiling followed by scenes of chaos inside the club, with young people running through the smoke as the musicians urged them to escape as quickly as possible.

“We even tried to get out through the bathroom, only to find bars (on the windows),” Marija Taseva, 19, told The Associated Press, describing the fire that erupted after watching a local pop group at Club Pulse. “I somehow managed to get out. I fell down the stairs and they ran over me, trampled me. … I barely stayed alive and could hardly breathe.” She suffered an injury to her face.

The fire caused the roof of the single-story building to partially collapse, revealing the charred remains of wooden beams and debris. Police cordoned off the site and sent in evidence gathering teams in an operation also involving state prosecutors.

Interior Minister Panche Toshkovski said 15 people were detained for questioning after a preliminary inspection revealed the club was operating without a proper license. He said the number of people inside the club was at least double its official capacity of 250.

“We have grounds for suspicion that there is bribery and corruption in this case,” he told reporters without elaborating.

The fire is the worst tragedy in recent memory to befall the landlocked nation, whose population is less than 2 million, and the latest in a slew of deadly nightclub fires around the world.

Condolences poured in from leaders around Europe as well as from the office of Pope Francis, who has been hospitalized for a month for double pneumonia.

European Commission President Ursula von der Leyen and Ukraine President Volodymyr Zelenskyy also sent messages of support. “I wish those who were injured a speedy recovery. Ukraine mourns alongside our (North) Macedonian friends on this sad day,” Zelenskyy wrote in a post on X.

Health Ministry officials said the government had accepted offers of assistance from several neighboring countries, including Bulgaria, Greece, Serbia and Turkey, where preparations were being made to receive patients with life-threatening injuries.

In the northern Greek city of Thessaloniki, three people with severe burns aged 25, 25 and 19 were being treated at a civilian hospital, with one undergoing surgery, health authorities said. Their conditions are critical.

Throughout Sunday, relatives gathered in front of hospitals and city offices in Kocani, some 115 kilometers (72 miles) east of the capital, Skopje, begging authorities for more information. Resident Dragi Stojanov was informed that his 21-year-old son Tomce had died in the fire.

“He was my only child. I don’t need my life anymore. … 150 families have been devastated,” he said. “Children burnt beyond recognition. There are corpses, just corpses inside (the club). … And the bosses (of organized crime), just putting money into their pockets.”

President Gordana Siljanovska-Davkova visited burn victims at a hospital in Skopje and spoke to parents waiting outside.

“It’s terrible … hard to believe how this happened,” she said, her voice halting with emotion. “We must give these young people courage to continue.”

Prime Minister Hristijan Mickoski said late Sunday it had been “the most difficult day of my life,” adding that the country must defeat corruption.

“I entered politics to change something. I encountered a deeply corrupt system that has been created and nurtured for decades, which includes people from all parties, from all profiles. If that system does not collapse, this country will never exist,” he said in a statement.

North Macedonia’s government ordered a sweeping inspection to be carried out at all nightclubs and cabarets across the country over the next three days.

Pyrotechnics have often been the cause of deadly fires in nightclubs, including the one at the Colectiv club in Bucharest, Romania, in 2015 in which 64 people died.

Associated Press writers from across Europe contributed to this report.