Key developments on Sept. 13-14: * Ukrainian drones strike major Russian oil refinery in Leningrad Oblast, governor says * Ukrainian drone hits chemical plant in Russia's Perm Krai 1,800 km from border, source says * Ukraine hits Russia's Black Sea Fleet communication hub in occupied Crimea, Navy says * Ukraine behind attack on Russian railway logistics, undermining offensive capabilities, military intelligence source claims * Romania scrambles jets, Poland closes airport over Russian dron