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.

Recent social media videos show Ukrainian forces using drones similar to IEDs. The drones sit next to roads and then strike Russian military vehicles when they pass.

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.