Authorities launch criminal proceedings after man allegedly fired a flare gun during a confrontation, setting the nightclub alight.
At least 13 people died in an overnight fire at a nightclub in the Russian city of Kostroma and police detained a man suspected to have ignited it by firing a flare gun.
Video shared by investigators on Saturday showed firefighters spraying water on what appeared to be the smouldering, collapsed roof of the building.
The fire took place at Polygon, a multipurpose recreation venue used as a cafe, nightclub and bar.
“As a result of the fire, 13 people died. The number of dead and injured is being clarified,” the judicial investigating committee said in a statement.
TASS news agency cited investigators as saying the fire may have started after a man fired a flare gun indoors.
Witness testimony suggested the man may have been angered after his advances were spurned.
“He was spending time in the bar with a woman, ordered her flowers, with a flare gun in his hands,” an unnamed witness told the Russian news agency. “Then he went to the dance floor and fired it.”
Rescuers evacuated 250 people from the building while more than 50 firefighters worked to extinguish the blaze.
The fire put out at 7:29am (04:29 GMT), according to the regional governor, who put the number of injured at five.
Kostroma, a city of about 270,000 people, is 300km (190 miles) northeast of Moscow on the banks of the river Volga.
In 2009, someone set off fireworks at the Lame Horse nightclub in the Russian city of Perm, killing more than 150 people.