At least 13 people died after a fire broke out in Polygon nightclub in the Russian city of Kostroma, officials said on Saturday, as Reuters reported.
The state TASS news agency cited investigators as saying the fire started after a man fired a flare gun indoors, setting the ceiling alight. Police have now detained a man in connection with the incident, the interior ministry said.
Most of those killed in the fire had been found in the smoking room, utility room and near the toilets, emergency services said.
There have been at least five other fires at restaurants since the start of the year, of which two resulted in deaths.