Ukrainian President Volodymyr Zelensky called the airstrikes a “manifestation of Russian madness.”
Dozens of people were killed or injured in an airstrike on a large hardware store in the Ukrainian city of Kharkiv on Saturday afternoon, local authorities said.
Regional governor Oleh Shnievbov said two guided bombs landed at a DIY supermarket in a residential area of ​​the city, killing six people and wounding 40.
Sixteen people are still missing.
The airstrikes sparked massive fires and images on social media showed huge columns of smoke filling the sky.
Kharkiv Mayor Igor Terekhov said a second bomb had fallen in the city's central park.
President Zelensky called the airstrikes a “manifestation of Russian madness” and called on Western countries to provide Ukraine with air defense systems.
“When we tell world leaders that Ukraine needs adequate air defense, we are literally speaking about how we will not tolerate terrorist attacks like this,” he said in the X post.
“Only the madmen [Russian President Vladimir] Putin is capable of killing and terrorizing people like this,” Zelensky added.
Moscow denies that it deliberately targeted civilians.
The Kharkiv region is located about 30 km from the Russian border.
Moscow's forces have seized villages in the region in recent weeks as part of a wider offensive, and analysts say they may be trying to come within artillery range of the city of Kharkiv.
Ukrainian authorities have evacuated more than 11,000 people from the area since the offensive began on May 10.
Russia's Kharkiv offensive appears to be a coordinated new offensive that also tests Ukrainian defenses further south in the Donetsk region, where the Russian Defense Ministry said on Saturday that Russian forces had taken control of the village of Arkhanherske.
They also launched incursions into the northern Sumy and Chernihiv oblasts.
Russian President Vladimir Putin said Kremlin forces were trying to create a “buffer zone” in the Kharkiv region to prevent attacks from across the Ukrainian border.