At least four people died overnight as Russian drone and missile strikes continued to pound Ukraine’s towns and cities, local officials said Saturday. Meanwhile, Moscow’s troops continued their grinding advance through the country’s east.

Russia launched a barrage of drones and missiles on Ukraine on Saturday, killing at least four civilians and damaging residential buildings and infrastructure across the country, Ukrainian officials said.

Russia and Ukraine exchanged large drone attacks on Sunday night into Monday, with alleged Ukrainian UAVs forcing flight restrictions at three Russian airports.