A fuel depot in the Russian city of Belgorod is on fire Friday after Ukrainian helicopters reportedly crossed the border and attacked the facility, the governor of the region said on social media, claims that have not been independently verified but if true would mark the first Ukrainian airstrike on Russian territory.

Ukraine strikes fuel depot in Russia's Belgorod, regional governor says

A screen grab from a video shows firefighters responding to a fire at a fuel depot. The photo was taken by the Russian Ministry of Emergency Situation.

Anadolu Agency via Getty Images

The oil depot was set ablaze and two workers were injured when two military helicopters bombed it.

The claims have not been independently verified or claimed by Ukrainian officials.

It would be the first Ukrainian airstrike on Russian territory since the war began.

The reports add to growing indications of strong resistance against Russian forces, with Ukraine continuing to make successful but limited counter attacks to the east and north east of Kyiv.

The defense ministry said late on Thursday that Russia is reinforcing the invasion of Georgia.

The ministry said it was highly unlikely that Moscow would create reinforcements like this.

PLAY Full Screen About Connatix 1/1 Skip Ad Continue watching after the ad Loading PodsVisit Advertiser websiteGO TO PAGE

Russian attacks change focus. Moscow promised to reduce military activity in northern Ukraine this week and said it would focus on securing the eastern Donbas region. Russia's claims could be an effort to regroup and hide military failures, according to analysts and officials. Reports suggest that attacks in eastern Ukraine are intensifying and that there is no sign of abating in western Ukraine. The British defense ministry says that Russian forces have been forced to return to their home countries to replenish and reorganize, as well as redeploying Georgian troops.

According to the nuclear agency of Ukraine, the Chernobyl power station has been placed back under Ukrainian control after Russian soldiers left after receiving high doses of radiation. The UN atomic watchdog said on Friday that the reports have not been independently verified.

The governor of the Russian region says that the fuel depot in Belgorod was hit by the Ukrainians.

The IAEA is investigating a claim that Russians fled Chernobyl with radiation sickness.