BUENOS AIRES (AFP) - Five young people died and five others were in critical condition after apparently taking drugs at an international electronic music festival in the Argentine capital, emergency responders said on Saturday (April 16).

Autopsies will be needed to determine the substance involved, said Dr Alberto Crescenti, head of the emergency healthcare system, which was summoned to the Time Warp music festival in Buenos Aires in the early morning hours.

The partygoers were mostly between the ages of 21 and 25, Dr Crescenti said.

"The youths lost consciousness and rapidly went into a coma," he said.

Those in hospitals were in critical condition and had temperatures of 42 deg C, indicating severe poisoning, Dr Crescenti said.

Organisers of the show at a venue on the city's riverside north end had two ambulances ready and waiting for the packed crowd of nearly 11,000 people.

But they were not enough, and the emergency services brought in six.

"There were a great deal of people. It was really hot inside. You could not be in there, literally," a young man who gave his name as Federico told TN news channel.

He said he left the event five minutes before it closed at 6am, with no idea of the unfolding tragedy.

Another at the festival, Ignacio, told C5N TV that "people were offering drugs, pills, acid. They tried to sell me drugs four times".

It was the third Time Warp festival in Buenos Aires. The city government said that the venue, a large private events and exhibition center, had been approved to hold the festival and host as many as 13,000 people.

Prosecutors have urged people at the event to share any information that could help in their investigations and offered protection to potential witnesses.

Time Warp is a well-known electronic music festival, originating in Germany about two decades ago.

The line-up in Buenos Aires included DJs such as Sven Vath, Jamie Jones, Ricardo Villalobos, Maceo Plex and Tale Of Us.

The second night of the event, scheduled for Saturday, was cancelled.