Ukraine has conducted a series of drone attacks on targets in Russia.

A Ukrainian minister says a Ukrainian drone flew more than 1,200 kilometers.

Russia's defense ministry said on Friday that its forces shot down a Ukrainian unmanned aerial vehicle, or UAV, in the western Russian region of Bryansk in the morning.

The regional governor said that oil tanks at a storage facility in the town of Klintsy caught fire after the UAV was brought down.

The defense ministry announced a day earlier that the military downed Ukrainian drones near the capital Moscow and in the northwestern region of Leningrad, which surrounds Russia's second largest city of St. Petersburg.

Independent media outlets in Russia say an explosion occurred at a large oil terminal at a port in St. Petersburg in the wake of the failed drone attack by Ukraine.

They also reported it may be the first case in which Ukraine targeted the area.

Ukraine's minister for strategic industries, Oleksandr Kamyshin, told reporters that a Ukrainian drone flew exactly 1,250 kilometers and hit a target.

Russian forces apparently continued to attack cities across Ukraine using Iranian-made drones and their upgraded models.

A US think tank, the Institute for the Study of War, said in its assessment on Thursday that "the battlespace in Ukraine continues to be the center of the technological offense-defense race between Russian and Ukrainian forces."