Two low-flying Ukrainian helicopters crossed into Russian territory early Friday and fired on an oil depot in the city of Belgorod, a regional governor said — the first time Russia has reported a Ukrainian airstrike on its territory since the war began.

The strike appeared to be an embarrassment to Russia’s military, which said last week that Ukraine’s air force had been “practically destroyed.” Ukraine’s military had previously only managed to hit Russian territory with ground-launched missiles.

Belgorod, which has a population of about 400,000, sits less than 20 miles from the Ukrainian border. The region has been a staging ground in recent weeks for Russian troops entering eastern Ukraine.

Video posted to VKontakte and verified by The New York Times shows two helicopters firing at the oil depot on the eastern edge of the city. Although it was not possible to determine whether the helicopters were Ukrainian, the footage confirmed that an airstrike caused a fire at the site. Other video of the aftermath shows the facility continuing to burn into the daylight.