Mysterious drones hit a major Russian oil refinery in Novoshakhtinsk in the Rostov region, which is near the border with Ukraine, the plant's management said Wednesday. The incident came as the fight between Ukraine and Russia is about to enter its fifth month. The strike sent a ball of flame and black smoke straight into the sky, prompting the suspension of operations, the authorities told local media. A video was shared on the Telegram messaging service, showing a twin-boom tail configured drone crashing into the Russian oil refinery. There are speculations it was a "kamikaze" drone strike conducted by the Ukrainian Armed Forces, according to the Drive.