Shoppers were injured as an explosion ripped through a St Petersburg supermarket on Wednesday.

Russian authorities are investigating the cause of a blast, thought to have left at least four people hurt.

The explosion happened at the market in the city’s north-west Kalininsky district.

According to Russian news agencies, the St Petersburg’s branch of the Emergencies Ministry reported that a device containing 200 grammes of explosive material had been placed in a storage locker for customers’ bags.

Experts are now investigating the cause of the blast.

Earlier this month, Russian President Vladimir Putin telephoned US President Donald Trump to thank him for a CIA tip that helped thwart a series of bombings in St Petersburg, including a suicide attack reportedly planned for December 16.

In April, a suicide bombing in the St Petersburg subway left 16 people dead and more than 50 wounded.