According to the BBC news website 27 have died and 155 injured following a fire in the collective nightclub, a former factory building.
The fire is believed to have been caused by fireworks that were let off inside the club.
"The only information we have is that fireworks were used in the club and after that the tragedy happened. Of course, this is under investigation," Mr Arafat, head of the emergency response teams, told the BBC.
The pyrotechnics were reportedly part of a show by a heavy metal band.
Witnesses said a spark on the stage ignited some of the polystyrene decor. A pillar and the club's ceiling caught fire and there was an explosion and heavy smoke, they added.
"People were fainting, they were fainting from the smoke. It was total chaos, people were trampling on each other," Victor Ionescu, who was at the club, told local TV station Antena 3.
Local journalist Sorin Bogdan told the BBC the club was in a converted former factory with two small exit doors, only one of which was possible to open initially.
A witness quoted by Romania's state news agency said terrified concert-goers had to break the second door down to escape.
Many of those being treated in hospital were suffering from smoke inhalation and severe burns, Mr Arafat said.
There appear to be So many parallels with other disasters why do people never learn?