The Russian Belgorod region bordering Ukraine was hit by strikes on Sunday, leaving at least four people injured in the latest attacks in the area, Russian officials said.<br /><br />Around 16 explosions were recorded in the city of Belgorod, Russia's investigative committee, which investigates serious crimes, said Sunday.<br /><br />The city of 330,000, around 40 kilometres (25 miles) from the Ukrainian border, had until recently rarely been hit, unlike the surrounding region.<br /><br />The attacks come a day after an oil depot was hit in the same area.