Ukraine destroyed a Russian submarine in Crimea on Friday, Kyiv's military has said, appearing to mark the latest blow to the Black Sea Fleet based around the peninsula to the south of mainland Ukraine. Ukraine "successfully struck" Russia's Rostov-on-Don submarine in the southern Crimean port city of Sevastopol, Kyiv's military said on Saturday. Kyiv also targeted four launchers belonging to Moscow's advanced S-400 air-defense systems on the Crimean peninsula, Ukraine's general staff said... "As a result of the hit, the boat sank on the spot," Ukraine's armed forces said. It had an estimated cost of around $300 million, according to...