Moldova’s president, Maia Sandu, is convening a meeting of her security council on Tuesday following a series of incidents in the breakaway Moldovan republic of Transnistria and a warning from Moscow that the Russian-backed region could be drawn into the war in Ukraine. Transnistria, which borders western Ukraine, is controlled by pro-Russia separatists and permanently hosts 1,500 Russian troops as well as a large arms depot. Last week, a senior Russian commander said the goal of Russia’s new offensive was to seize control of southern Ukraine and to gain access to Transnistria, creating worries that the small east European country...