The more drones in a single attack, Kuzan says, the more Ukraine hard-pressed air defence units struggle to shoot them down. This forces Kyiv to fall back on its precious supply of jets and air-to-air missiles to shoot them down.

Authorities said the boy died following a strike on a village in Kherson amid Russia's increased bombardment of Ukrainian cities.

Ukrainian officials say Russia has fired more than 700 attack and decoy drones at Ukraine overnight. That tops previous nightly barrages for the third time in two weeks.