A fire burned at a Russian oil refinery in the Rostov region, video posted on Thursday, 19 December shows.
Local governor Yuri Slyusar said Russian air defence systems repelled a Ukrainian attack in which 10 missiles were fired at the Rostov region.
Footage posted on social media showed the Novoshakhtinsk oil refinery engulfed in flames.
It was the second time in six months that the facility had been hit.
Slyusar said emergency crews were dispatched to the fire and details on casualties were being clarified.