Tragedy has struck on day one of Time Warp Argentina, with five people reported dead there.
Aged 21 to 25 years old, two died during the event, while three others died on the way to the hospital.
Another five attendees, including an 18-year old woman, remain in critical condition.
Alberto Crescenti, the head of the emergency services, said the victims were suspected of acute poisoning at the festival, which had gone out of control. “We'll see what substances they took,” he said.
Reports are coming through that the event was overcrowded and that some fans were having difficulty breathing in the badly ventilated at the Costa Salguero venue.
"We couldn't stay inside, we couldn't breathe," one of the participants told a local TV station.
"It was too hot and there were too many people.
Time Warp has issued a statement via their main Facebook page, saying:
"We express our deepest condolences to the families and friends of the people who passed away. The cause of this tragedy will take some time to determine. The show is cancelled for tonight.
We will let you know as soon as possible how you can refund the ticket for tonight. We ask that you keep the loved ones of these people in our thoughts and prayers."
Time Warp is a German techno festival that has been running in various countries around the world since 1994. This was the third year that they had brought the event to the Argentine capital.
H/T BBC. Image via