Two buildings were damaged following an unspecified "incident" in St. Petersbug's Krasnogvardeisky district early on March 2, the city's governor, Alexander Beglov, reported.
The governor's statement comes amid claims spread on Russian Telegram channels that Russia's second-largest city came under a Ukrainian drone attack.
According to the Mash Telegram channel, the likely target was the Ruchi oil depot northeast of St. Petersburg, less than one kilometer from the crash site.
Footage published on Mash shows damaged balconies of a multi-story residential building and what the authors claim to be a fragment of a drone.
Another recording partially captures a strong explosion over the building, with shards of glass and other debris falling on the ground.
Beglov said that the residents of the affected buildings were evacuated, and emergency services are working on site.
Six people sought assistance after the incident, and one person was hospitalized, the Russian state-owned news agency TASS reported, citing health officials.
The Kyiv Independent could not verify the claims, and Ukrainian officials have not commented on the incident.
The news comes the same day when Ukraine came under a large-scale Russian drone attack, killing and injuring people in Odesa and Kharkiv oblasts.
Alleged drone attacks against Russian oil depots and refineries have become a common occurrence in recent months, with incidents reported in multiple regions, including Bryansk, Oryol, and Leningrad oblasts.