The first blaze broke out at a civilian facility carrying 10,000 tons of fuel, followed by a second at a separate depot with 5,000 tons, per The Guardian. Bryansk, which is situated less than 100 miles from the border with Ukraine, acts as a logistics base for Moscow in the ongoing war.
Though there is speculation online that the fires were the result of a Ukrainian missile strike, there was no "immediate indication" that one or both of the fires were related to Ukraine, Reuters writes.
"It sounds like something is flying through the air before the explosion," military analyst Rob Lee told The Guardian, referencing the footage circulating on social media. "I think it was probably a Ukrainian attack, but we cannot be certain."
If it was the Ukrainians, Lee estimates the attack to have been an attempt at disrupting Russian military fuel supplies.
There has been no immediate comment on the incident from Ukraine.
Last week, Russian officials claimed Ukrainian helicopters had attacked residential buildings and injured seven individuals in the Bryansk region. The Ukrainian Defense Ministry did not respond to a request for comment on the alleged incident at the time, per Reuters.