Dozens of firefighters are working to put out a blaze that is burning at an oil depot in St. Petersburg, Russian authorities said.

Videos from the area posted on social media show a large plume of black smoke rising as explosions ring out.

The fire was first reported at 10:59 a.m. local time, Russia's Ministry of Emergency Situations said. A hangar of 80 by 10 meters (262 by 33 feet) is up in flames, but the full area of the conflagration is still being determined, the ministry said. Sixty firefighters and 12 emergency vehicles were on the scene as of around 1 p.m.

Russian online news outlet Fontanka reported the fire was at the Ruchi oil depot.

The cause of the incident is not yet known. No casualties have been reported so far.