Russian forces launched a large-scale nighttime attack using drones on the Kharkiv region in Ukraine, resulting in 21 injuries and the destruction of residential buildings and storage facilities, according to reports from emergency services and local officials on Thursday.

Emergency services reported that the attacks caused four fires in Ukraine’s second-largest city.

The Ukrainian Air Force announced that it shot down 42 out of 86 drones launched by Russia during the attack, noting that 26 other drones failed to reach their targets.