Sheltering Ukrainians painted the word "children" outside a theatre in a desperate but futile attempt to deter a Russian attack.
The large letters spelling out the Russian script warning came before forces went on to drop a powerful bomb on the theatre that was being used as a shelter for families in Mariupol, Ukraine.
The city council said it's "impossible to estimate the scale of this horrific and inhumane act" and that efforts were underway to find the identities of the victims - and just how many innocent Ukrainians were slaughtered.
They confirmed the central part of the venue was completely destroyed, as was the entrance to an area being used as a bomb shelter.
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The statement went on: "It is impossible to find words that could describe the level of cruelty and cynicism with which the Russian occupiers are destroying the civilian population of the Ukrainian city by the sea.
"Women, children, and the elderly remain in the enemy's sights.
"These are completely unarmed peaceful people.
"It is obvious that the only goal of the Russian army is the genocide of the Ukrainian people."
They added that Ukrainians will "never forgive" Moscow for "this crazy war".
"We will never forgive and never forget," the statement read.
An official in the Mariupol mayor's office said on Thursday the city authorities did not yet have a casualty toll after what they said was a Russian bombardment of a theatre in the besieged Ukrainian city.
Russia's defence ministry on Wednesday denied it had carried out an air strike against a theatre in Mariupol, RIA news agency said.
It comes after Ukrainian shoppers queuing for bread were executed in cold-blood yesterday in the latest war crime committed by Russian troops.
Shocking claims by America accused the soldiers of shooting people as they queued for bread in the embattled northern city of Chernihiv.
It was originally reported that 10 people had died but the death toll has since risen.
There are growing fears the faltering Russian advance, beset by shocking troop and equipment losses, has led to soldiers picking out innocent civilians.
Even before midday yesterday (Wed) three bombers were shot down as it emerged 13,800 Russian troops had died in just 21 days of fighting. Within hours a Russian helicopter was blown out of the sky.
US embassy officials tweeted: “Today, Russian forces shot dead and killed ten people standing in line for bread in Chernihiv.
“Such horrific attacks must stop. We are considering all available options to ensure accountability for any atrocity crimes in Ukraine.”
