Despite the changes in warfare, Russian forces retain the ascendancy and are making slow but steady advances in the east and north of Ukraine. Russia has also caught up in UAV technology after falling behind early in the war, according to military analysts, and like its enemy is churning out drones domestically at a rate of millions a year.

Russia pounded Ukraine with hundreds of drones and missiles overnight and Saturday as part of a stepped-up bombing campaign that killed at least six people and wounded dozens, officials said.

Hundreds of Russian attack drones and more than two dozen cruise missiles targeted Ukraine overnight, killing at least two people, Ukraine said.