A huge fire has destroyed a large warehouse outside St Petersburg used by Wildberries, the online retailer known as “Russia’s Amazon”.

Up to 1,600 people were working in the building early on Saturday morning when the warehouse caught alight, reports said.

There were no casualties but the TASS news agency reported that many of the workers had to run for their lives because fire alarms had been turned off.

Video showed dozens of people fleeing down fire escapes. In one video shot inside the warehouse, the fire engulfs rows of shelves as people run away.

“The roof is falling in! Get out! Get out quickly!” a man shouted in the video. There was no alarm sounding.

A video shot from a passenger jet flying overhead showed flames gutting the warehouse, which was roughly the size of 10 football pitches, and thick black smoke billowing into the sky.

Emergency services said that 57 fire engines and 270 firemen had been deployed to tackle the fire, which it rated at a severity level four out of five.

Russia has a poor fire safety record. In 2018, more than 60 people, mainly children, died in a fire at the Winter Cherry shopping complex in Kemerovo, Siberia, because the staff ran away, fire alarms did not sound and many fire escape doors were locked.

Russian media said that authorities were investigating potential arson at the Wildberries warehouse fire, although they didn’t name any suspects. There were several fires last year at factories and businesses linked to Vladimir Putin’s war in Ukraine.

Like most Russian businesses, Wildberries has supported Putin’s war in Ukraine.

Before Christmas, police raided a Wildberries packing centre in Tula, south of Moscow, in an operation to detain migrant workers and then send them to fight in Ukraine.