Ukraine’s security service released footage Wednesday of its attack on Russian war planes at multiple airbases across the country. In the span of a few hours on Sunday, nearly a third of Moscow’s strategic bomber fleet was destroyed or damaged with cheaply made drones sneaked into Russian territory, according to Ukrainian officials.

Russia said on Sunday its forces had advanced to the edge of the east-central Ukrainian region of Dnipropetrovsk amid a public row between Moscow and Kyiv over peace negotiations and the return of thousands of bodies of soldiers who fell in the war.