Oil tanks near Russia's border with Belarus and Ukraine caught fire early Wednesday, local authorities said Wednesday.

The oil tank fires come a day after Russian regions bordering Ukraine reported one of the widest spates of shelling attacks on their territory since the start of Moscow's invasion of its western neighbor.

Bryansk region Governor Alexander Bogomaz wrote on social media that tanks with petroleum products were burning in the Surazhsky district located 10 kilometers south of Belarus and 40 kilometers north of Ukraine’s Chernihiv region.

The fire spread to an area of 4,000 square meters, the state-run TASS news agency reported, citing emergency services.

Bogomaz said the blaze was contained three hours later.

He said there were no casualties.

The fire may have been caused by an unidentified munition dropped from a drone, the pro-Kremlin Izvestia newspaper reported, citing unnamed emergency sources.

If confirmed, Wednesday’s attack would follow at least three cross-border strikes on Russia’s border regions of Kursk and Belgorod on Tuesday.

While there were no casualties in these attacks, the regions’ governors said they caused damage to power supply facilities and at least one gas pipeline.

Kyiv has neither claimed responsibility for nor denied attacks on Russian territory.

Ukraine itself is reeling from near-daily Russian missile and drone strikes since Oct. 10 which have almost knocked out the country’s power grid and plunged millions of Ukrainians into darkness and winter cold, Moscow Times reports.