“The search and rescue operation is ongoing,” Klymenko said. “There may still be people under the rubble.”
Zelensky, who was attending a European summit in Spain, condemned the attack on social media.
“The brutal Russian crime of hitting an ordinary grocery store with a rocket is a completely deliberate terrorist attack,” he wrote.
The attack took place in the Kupiansk district of the war-battered region bordering Russia, where Moscow’s forces have been pushing to recapture territory they lost last year to Ukrainian troops.
‘True evil’
The head of the Kharkiv region Oleg Sinegubov said the strike took place around 1:15 p.m. (10:15 GMT).
The village is west of Kupiansk, a frontline town in the region where officials have recently ordered mandatory evacuations after an uptick in Russian strikes.
Zelensky’s adviser Mykhailo Podolyak said the attack had “no military logic.”
“This is a reminder to anyone who is willing to smile and shake hands with war criminal Putin at international conferences,” he said, referring to Russian leader Vladimir Putin.
“A reminder to all those who want to sell something to Russia and return to bloody business as usual,” he said, adding: “Putin’s Russia is a true evil.”
Defense Minister Rustem Umerov said the strike showed Ukraine needed more air defense “to protect our country from terror. We are discussing this with partners.”
Large swathes of the Kharkiv region were captured by Russian forces in the early days of their invasion launched in February last year.
Ukrainian forces recaptured much of the border territory during a lightning offensive late last year, but the regional capital, also called Kharkiv, is still subjected to routine shelling.