Story highlights Witnesses say the fire started quickly, there was heavy smoke

Spokeswoman for the Interior Ministry says many injured are in critical condition

At least 27 people were killed at the Colectiv nightclub, where a heavy metal band was playing

(CNN) Hundreds of young people were packed into a music club in central Bucharest, Romania, jamming to the head-pounding heavy metal music filling their ears.

It was almost Halloween. The band, Goodbye to Gravity, was celebrating a new album with a free concert. For the young partygoers life was awesome.

But suddenly the 300 or 400 people were scrambling toward the one exit at Colectiv, a club built inside a Communist-era factory.

Witnesses say pyrotechnics sparked a fire that quickly became a widespread blaze with dark, blinding smoke. Authorities say the cause is something that needs to be figured out.

At least 27 people died and 162 were injured when the blaze broke out late Friday, authorities said.

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