At least three people were killed and several others were wounded in Ukrainian drone attacks against regions in southern Russia overnight, local authorities said early Wednesday.

In the Belgorod region, which is struggling to restore power, heating and water after Ukrainian strikes this weekend, Governor Vyacheslav Gladkov reported the deaths of two civilians as a result of drone attacks.

Further to the south, in the city of Rostov-on-Don, a drone crashed into an apartment building, Rostov Governor Yury Slyusar said. A man was killed after an apartment caught fire, he added.

Four other people, including a four-year-old child, were wounded in drone strikes elsewhere in the Rostov region, which sparked fires at several industrial sites, according to Slyusar.

Russia’s Defense Ministry said it destroyed 48 Ukrainian drones across Russia and annexed Crimea overnight. More than half of those drones were downed in the skies above the Rostov region, the ministry said.

Meanwhile, in Ukraine, military authorities reported downing more than 100 Russian drones that were launched at the country overnight.

Both Ukraine and Russia regularly launch drone and missile attacks at each other’s territory, with officials in Kyiv justifying their strikes as retaliation for Russia’s full-scale invasion and ongoing occupation of Ukrainian territory.

In particular, Ukraine has intensified strikes on Russia’s energy infrastructure since the summer in an effort to cut Moscow’s oil revenues, a key source of funding for its war effort.