Russian forces have fired drones at two apartment buildings and a power plant in Ukraine’s second-largest city, killing four people, local authorities said.
Shahed drones smashed into two apartment buildings in Kharkiv, near the Russian border, which has frequently been targeted during more than two years of war.
Other drones targeted the power grid.
The Kremlin’s forces in recent months have stepped up their aerial barrages of Ukraine, hitting urban areas.
The approximately 1,000-kilometre (620-mile) front line is largely deadlocked, but Kyiv officials say Moscow’s troops have recently been probing for Ukrainian weaknesses on the front line ahead of an expected large-scale Russian offensive in the summer.
The Institute for the Study of War said the goal of Russia’s escalated attacks on civilian areas and the country’s power grid may be to compel Ukraine’s army to deploy air defence systems away from the front line.
That would allow Russia to provide more air cover for its ground operations on the battlefield, the think tank said.
Russian forces have apparently increased the scale of their mechanised ground assaults in parts of the front line in recent weeks, it added, apparently seeking gains while Ukrainian forces are kept waiting for the arrival of vital new military supplies from their Western partners.
With the support of China, Russia has built its forces back up close to full strength, according to a senior US official.
“We have assessed over the course of the last couple of months that Russia has almost completely reconstituted militarily,” US deputy secretary of state Kurt Campbell said on Wednesday.
In Kharkiv, three first responders were killed when Russia struck a multistorey building twice in quick succession, local authorities said.
Six people were wounded at that location.
Another 14-storey building was hit by a drone, killing a 69-year-old woman.
Ukrainian officials have previously accused Russia of targeting rescue workers by hitting residential buildings with two consecutive missiles – the first one to draw crews to the scene and the second one to wound or kill them.
The tactic is called a “double tap” in military jargon.
Russians used the same method in Syria’s civil war.
Other first responders have also been victims of the fighting.
The World Health Organisation (WHO) said on Thursday that ambulance workers and other health transport staff face a high risk of injury or death.
“Many emergency teams come under fire either on the way to a call or at their bases,” the WHO said in a report.
“This is a horrifying pattern,” Dr Emanuele Bruni, the WHO’s incident manager in Ukraine, was quoted as saying in the report.
“These attacks threaten their safety and further devastate communities that have been living under constant shelling for more than two years.”
Ukrainian soldiers shot down 11 of the 20 drones Russia launched against Ukraine during the night, the General Staff said.
Russia also attacked energy infrastructure in the Kharkiv and Dnipropetrovsk regions over the past day, wounding two people, the Ministry of Energy said on Thursday.
Some 700,000 people in Kharkiv lost power last week after a massive missile attack hit the city’s thermal power plant.
Repairs are ongoing.
“Each manifestation of Russian terror once again proves that the country-terrorist deserves only one thing – a tribunal,” Ukraine’s human rights chief Dmytro Lubinets said on Telegram in response to the attack.
