Three young girls have died and another two are in a critical condition in hospital after suffering cardiorespiratory arrests during a stampede at a private Halloween party in the Madrid Arena last night.

Emergency services received a call around 4 o'clock this morning to come to the aid of a group of young girls aged between 18 and 25, who were all in trauma-provoked cardiorespiratory arrest as the result of being crushed by the mass of people in the venue.

Two of the girls died in the first aid centre at the venue, after paramedics had spent more than 30 minutes trying to reveive them. The third died on arrival at the Hospital Clínico and the other two are in a critical condition at the 12 de Octubre Hsopital and the Fundación Jiménez Díaz respectively.

The police investigation is ongoing, but initial reports suggest that the stampede was prompted by someone launching a flare which unleashed panic in the crowd.

One of the partygoers said that there was only one exit open and that "all the others were sealed shut". There are many similar recriminations on Twitter and other social networks, many complaining that twice as many tickets were sold than the venue's capacity. "Removing corpses before our very eyes.... unbelievable" said one Twitter user.

Other partygoers did not hear about the tragedy until after the event. "We were up on the third floor and didn't hear about it until it appeared on the Internet", said one young person. "The organisers of the party wouldn't let us go down to the main floor because it was too crowded".