Ukraine's security service was behind another wave of drone attacks on Russian oil refineries overnight, a Ukrainian source has told Reuters.
The attacks in Ryazan, Kstovo and Kirishi were part of a wider push to hamper Russia's economic potential, they said.
"Judging by the videos online, the consequences were fairly significant," the source said.
They added that Ukrainian defence forces had launched drones at a Russian airbase in Buturlinovka and a military airfield in Voronezh region.
