STORY: Ukraine said 13 people died and 10 were wounded when Russia fired rockets at Marhanets from the territory of a nuclear power plant it has captured in the Dnipropetrovsk region.
"The armed forces of Ukraine, our intelligence and our law enforcement agencies will not leave today's Russian shelling of Dnipropetrovsk region unanswered," Zelenskiy said in a late-night video address.
The attack, he said, underlined the need for allies to supply more powerful weapons to the Ukrainian military.
"The more losses the occupiers suffer, the sooner we will be able to liberate our land and ensure the security of Ukraine," he said.
The war that began with Russian forces invading its neighbor on Feb. 24 has displaced millions, killed thousands of civilians and left cities, towns and villages in ruins. Ukraine and its Western allies have accused Russian forces of targeting civilians and war crimes, charges Russia rejects.
On Thursday defence ministers of Ukraine, UK and Denmark host ministers from allied countries in Copenhagen to discuss long-term support for Ukraine, including military training, mine clearance and weapon supplies.
Zelenskiy said he was grateful to his country's partners for understanding the safety of Ukraine and Europe depended on "making sure Russia loses on the battlefield."