About 1,500 people were attending a hip-hop concert in Kocani, in the vicinity of Skopie, North Macedonia, when the nightclub they were in caught fire.
It was early in the morning on Sunday when Pulse Club was engulfed by flames.
Videos show smoke billowing into the still-dark sky.
Local media say that the fire may have been caused by the use of pyrotechnic devices, with footage showing sparks from the stage catching on the ceiling before rapidly spreading, also reports the BBC.
51 are dead, dozens more are feared killed, and many others are seriously injured.
