Ukraine's second-largest city also suffered aerial attacks on its power plant, part of a pattern of strikes on civilian energy infrastructure.
ADVERTISEMENTLocal authorities in Ukraine's second-largest city, Kharkiv, reported that Russian forces launched drones at two apartment buildings and a power plant, resulting in the deaths of four people.
The attack comes as the Kremlin formulates its strategy for the coming months of conflict, which is expected to see an escalation in the targeting of civilian areas.
In recent months, Russian forces have intensified their aerial assaults on urban centres in Ukraine, particularly along the approximately 1,000-kilometre front line, which remains mostly static.
However, Ukrainian officials suggest that Russian troops have been testing weak points ahead of an expected major offensive in the summer.
According to the Institute for the Study of War, Russia's renewed attacks on civilian infrastructure and the power grid could be a tactic to divert Ukraine's air defence systems away from the front lines, thereby facilitating greater air support for Russian ground operations.
A senior US official confirmed to the Associated Press that Russia has reportedly rebuilt its forces to near full strength, apparently with the support of China.
Ukrainian officials have accused Russia of employing tactics such as the "double tap," where consecutive strikes target rescue workers responding to the initial attack, a method previously used in conflicts such as Syria's civil war.
In the latest Kharkiv strikes, three first responders lost their lives when a multistory building was struck twice in rapid succession by Russian attacks. Another building was hit by a separate strike, resulting in the death of a 69-year-old woman.
The World Health Organisation highlighted the grave risks faced by ambulance workers and health transport staff amid ongoing hostilities, with many coming under fire en route to emergencies or at their bases.
Ukrainian forces managed to down 11 of the 20 drones launched by Russia during the night, according to the General Staff.