The Russian strike echoed earlier attacks that caused large numbers of civilian casualties - such as one in March on a Mariupol theatre where many civilians were sheltering, killing hundreds of people - and another in April on a train station in eastern Kramatorsk that killed at least 59 people.
Mr Zelensky’s comments came as an extensive investigation by Amnesty International has concluded that Russian military forces committed a war crime when they struck the Mariupol drama theatre.
In a new report, ‘Children’: The Attack on the Donetsk Regional Academic Drama Theatre in Mariupol, Ukraine, the organisation documents how the Russian military likely deliberately targeted the theatre despite knowing hundreds of civilians were sheltering there on 16 March, making the attack a clear war crime.
Casualty figures rose as rescuers sifted through the rubble. The regional governor, Dmytro Lunin, said at least 18 people were killed and emergency services reported more than 60 were wounded.
In the first Russian government comment on the missile strike, the country's first deputy permanent representative to the United Nations, Dmitry Polyansky, alleged multiple inconsistencies that he did not specify, claiming on Twitter that the incident was a provocation by Ukraine.
Russia has repeatedly denied it targets civilian infrastructure, even though Russian attacks have hit other shopping centres, theatres, hospitals, schools and apartment buildings in the war. Russian media claimed that the missile had hit a store of Western weapons nearby and the resulting explosion had affected the shopping centre, which it claimed was not in operation.
The missile strike occurred as western leaders pledged continued support for Ukraine and the world's major economies prepared new sanctions against Russia, including a price cap on oil and higher tariffs on goods.
Meanwhile, the US appeared ready to respond to Mr Zelensky's call for more air defence systems, and Nato planned to increase the size of its rapid-reaction forces nearly eightfold - to 300,000 troops.
Mr Zelensky said the shopping centre presented "no threat to the Russian army" and had "no strategic value". He accused Russia of sabotaging "people's attempts to live a normal life, which make the occupiers so angry".
In his nightly address, he said it appeared Russian forces had intentionally targeted the shopping centre and added: "Today's Russian strike at a shopping mall in Kremenchuk is one of the most daring terrorist attacks in European history."
Amnesty International said the theatre attack in Mariupol was a “clear war crime”.
“After months of rigorous investigation, analysis of satellite imagery and interviews with dozens of witnesses, we concluded that the strike was a clear war crime committed by Russian forces,” said Agnès Callamard, Amnesty International’s Secretary General.
“Many people were injured and killed in this merciless attack. Their deaths were likely caused by Russian forces deliberately targeting Ukrainian civilians. The International Criminal Court, and all others with jurisdiction over crimes committed during this conflict, must investigate this attack as a war crime. All those responsible must be held accountable for causing such death and destruction.”