A Russian airstrike struck a bustling shopping mall in Kremenchuk, central Ukraine on Monday, setting the building ablaze and prompting concerns of mass casualties

Ukrainian President Volodymyr Zelensky said after the strike that up to 1,000 people were in the mall before the air raid was announced.

"Fortunately, as far as we know, at that time, many people managed to get out, they managed to get out, but there were still people inside  workers and some visitors,"

he said.

At least 15 people were killed, according to a Telegram post from Dmytro Lunin, the head of the Poltava region military administration, who said earlier that the death toll could rise.

At least 58 people were injured, Ukraine's State Emergency Services said.

Zelensky said in his nightly video address Monday that the rescue operation was ongoing and that

"we must be aware that the losses can be significant."

Video from the scene showed heavy smoke billowing from the building, which was engulfed by fire. The mall measures about one hectare roughly the size of two football fields and the strike occurred around 4 p.m. local time, Solohub said.

"We don't know how many more people might be under the rubble," said Volodymyr Solohub, a regional official in the Poltava Oblast local administration

Zelensky called the strike "one of the most defiant terrorist attacks in European history," in his evening video address.

"A peaceful city, an ordinary shopping mall with women inside, children, ordinary civilians inside."

"Only totally insane terrorists, who should have no place on earth, can strike missiles at such an object. And this is not an off-target missile strike, this is a calculated Russian strike exactly at this shopping mall," he said.

The attack targeted a site in central Ukraine far away from the epicenter of Russia's war, which has recently been focused in the east of the country.

It came as G7 leaders met at a summit in Germany that was mostly geared toward coordinating the Western response to Russia's invasion.

British Prime Minister Boris Johnson said from that meeting that the attack showed the "depths of cruelty and barbarism" of Russian President Vladimir Putin, the UK's PA news agency reported.

"This appalling attack has shown once again the depths of cruelty and barbarism to which the Russian leader will sink," Johnson said, according to PA.

In a tweet Monday, US President Joe Biden condemned the attack, saying, "Russia's attack on civilians at a shopping mall is cruel. We stand in solidarity with the Ukrainian people."

"As demonstrated at the G7 Summit, the U.S. along with our allies and partners will continue to hold Russia accountable for such atrocities and support Ukraine's defense," Biden added.

French President Emmanuel Macron called the attack an "abomination," in a tweet that included a video of the burning shopping mall.

"The Russian people have to see the truth," he said. And Ukraine's Foreign Minister, Dmitro Kuleba, said on Twitter: "Russia is a disgrace to humanity and it must face consequences.

The response should be more heavy arms for Ukraine, more sanctions on Russia, and more businesses leaving Russia." Those issues were on the table at the summit in Germany.

The G7 vowed to continue providing support for Ukraine "for as long as it takes" in a joint statement, and European Commission President Ursula von der Leyen told CNN on Monday that she would not "bet on Russia" winning the war.

The US plans to announce as early as this week that it has bought an advanced, medium-to-long-range surface-to-air missile defense system for Ukraine, a source familiar with the announcement told CNN.

However, despite the outward confidence of Western leaders, Russia has seen military successes in eastern Ukraine in recent days.

Russian forces captured the city of Severodonetsk after weeks of fighting and have also picked up territory south of Lysychansk.

They have eliminated most Ukrainian defenses in the Luhansk region and consolidated control of a belt of territory in the south, bringing strategic benefits and blunting the effectiveness of Ukrainian counterattacks.

Russian forces have also stepped up attacks in the Donetsk region, getting slightly closer to the belt of industrial towns in the region that runs south from Sloviansk through Kramatorsk to Kostiantynivka.

"Zelensky was very much focused on trying to ensure that Ukraine is in as advantageous a position on the battlefield as possible in the next months as opposed to the next years because he believes that a grinding conflict is not in the interest of the Ukrainian people,"

US national security adviser Jake Sullivan said after the Ukrainian President met virtually with leaders at the G7.

Earlier, a source familiar with the matter told CNN that Zelensky told leaders he wanted the war to be over by the end of the year, before winter sets in. - CNN

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