Moscow (AFP) - Russian police Saturday detained a man suspected to have caused a huge fire overnight at a bar in the city of Kostroma that killed at least 15 people.

Fire fighters fought through the early hours to put out the blaze at the popular Poligon bar in the city around 300 kilometres (180 miles) northeast of Moscow.

Russian agencies earlier reported that the fire could have started after a drunk man fired a “flare gun” on the dance floor.

“Police officers identified and detained the suspect (behind) unlawful acts in an entertainment establishment in the city of Kostroma, which resulted in a fire and the death of people,” Russian police said in a statement.

“He has now been handed over to investigative authorities,” it added, without providing any further details.

Russia’s Investigative Committee opened a criminal case of “causing death by negligence”.

State television showed images of the bar – housed in a single-storey logistical centre – engulfed in flames.

Authorities said the fire started at around 2:00 am local time and was put out at around 7:30 am.

Governor Sergei Sitnikov earlier said 13 people were killed, but emergency services then said the remains of two other people were found.

“Two more bodies were recovered. This means the number of victims is now 15,” the TASS news agency quoted law enforcement sources as saying.

Around 250 people were evacuated from the building when it caught fire, authorities said earlier.

- Flare gun on the dance floor -

The TASS news agency, citing sources in emergency services, said a drunk man with a “flare gun” was likely to have caused the fire.

“He was spending time in the bar with a woman, ordered her flowers, with a flare gun in his hands,” the source told the agency.

“Then he went to the dance floor and fired it.”

Local emergency services said the blaze had spread out over 3,500 square meters.

On its website, Poligon says it acts as an evening and night-time “place for recreation and entertainment”.

By day, it is a typical Russian “stolovaya” – a casual restaurant serving traditional food.

It says it is housed in a “distribution centre” and is popular with traffic police.

State television showed images of dozens of emergency workers fighting the inferno that had engulfed the building.

The sign “Poligon” was visible amid the flames raging on its roof.

One fire fighter told regional state television that it took 50 people to extinguish the fire and that they had used 20 fire engines.

He said the fire was especially difficult to put out because of the risk of the building collapsing.

Kostroma, a city on the Volga river of around 230,000 people, is one of Russia’s oldest cities and is famous for its medieval architecture and monasteries.

Russia, where there is often a lax approach to safety rules, has seen a number of deadly fires at entertainment venues in recent years.

In 2018, a huge fire killed 60 people in a shopping mall in the Siberian city of Kemerovo.

In 2009, another blaze at a nightclub in the Urals city of Perm killed 156 people.