Rescuers searched through charred rubble of a shopping mall on Tuesday looking for more victims of a Russian missile strike that killed at least 18 and wounded scores in what Ukraine's president called "one of the most daring terrorist attacks in European history."

President Volodymyr Zelensky said many of the more than 1,000 afternoon shoppers and workers inside the mall in the city of Kremenchuk managed to escape.               Giant plumes of black smoke, dust and orange flames billowed from the wreckage as emergency crews combed through broken metal and concrete for victims. Drones whirred above, clouds of dark smoke still emanating from the ruins several hours after the fire was extinguished.

Casualty figures rose as rescuers sifted through the smoldering rubble. The regional governor, Dmytro Lunin, said at least 18 people were killed and 59 others sought medical assistance, of whom 25 were hospitalised. The region declared a day of mourning Tuesday for the victims of the attack.

 "We are working to dismantle the construction so that it is possible to get machinery in there since the metal elements are very heavy and big, and disassembling them by hand is impossible," said Volodymyr Hychkan, an emergency services official.

At Ukraine's request, the UN Security Council scheduled an emergency meeting in New York on Tuesday to discuss the attack.

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 didn't 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 malls, theaters, hospitals, kindergartens and apartment buildings in the four-month war.

On Tuesday, Russian forces struck the Black Sea city of Ochakiv in the Mykolaiv region, damaging apartment buildings and killing two, including a 6-year-old child. A further six people, four of them children, were wounded. One of them, a 3-month-old baby, is in a coma, according to local officials.

The missile strike on Kremenchuk 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 Zelenskyy's call for more air defense systems, and NATO planned to increase the size of its rapid-reaction forces nearly eightfold - to 300,000 troops.

Zelenskyy said the mall presented "no tphreat 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 center and added, "Today's Russian strike at a shopping mall in Kremenchuk is one of the most daring terrorist attacks in European history."

He said Russia "has become the largest terrorist organisation in the world."

Russia has increasingly used long-range bombers in the war. Ukrainian officials said Russian Tu-22M3 long-range bombers flying over Russia's western Kursk region fired the missiles, one of which hit the shopping center and another that struck a sports arena in Kremenchuk.

The Russian strike echoed earlierattacks that caused large numbers of civilian casualties - such as one in March on a Mariupol theater where many civilians had holed up, killing an estimated 600, and another in April on a train station in eastern Kramatorsk that killed at least 59 people.

"Russia continues to take out its impotence on ordinary civilians. It is useless to hope for decency and humanity on its part," Zelenskyy said.

The United Nations called the strike "deplorable," stressing that civilian infrastructure "should never ever be targeted," UN spokesman Stephane Dujarric said.

 Group of Seven leaders condemned the attack in a statement late Monday saying "indiscriminate attacks on innocent civilians constitute a war crime. Russian President Putin and those responsible will be held to account."