Western allies vowed on Tuesday to boost NATO's defences and to back Ukraine to the end as Moscow demanded Kyiv's surrender.
As NATO leaders gathered in Madrid for a summit, alliance chief Jens Stoltenberg said Finland and Sweden would be formally invited to join NATO after Turkey lifted its block on their bids.
Turkish President Recep Tayyip Erdogan had stubbornly refused to approve their applications -- lodged in response to Russia's war on Ukraine -- despite calls from his NATO allies to clear their path to membership.
But he abandoned his opposition following crunch talks on Tuesday with the leaders of the two Nordic countries in Madrid.
Erdogan's office said late on Tuesday it had agreed to back their applications, saying Ankara had "got what it wanted".
British Prime Minister Boris Johnson hailed the agreement between Finland, Sweden and Turkey, saying their membership would make the defence alliance "stronger and safer".
Meanwhile, a senior US official said their membership would be a "powerful shot in the arm" for NATO unity.
NATO's expansion came as Russian missiles continued to pound Ukrainian cities.
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US National Security Advisor Jake Sullivan told reporters arriving with President Joe Biden that Washington will announce "historic" new long-term military deployments in Europe.
The reinforcements will join NATO's eastern flank, Russia's nervous neighbours like the Baltic states, and reflect a long-term change "in the strategic reality" elsewhere in Europe.
Ahead of the summit, Stoltenberg said the allies would boost their high-readiness forces from 40,000 to 3,00,000.
New sanctions
Before travelling to Madrid, Biden and other leaders of the G7 powers -- the world's richest democracies -- had held a summit in the German Alps.
Germany's Chancellor Olaf Scholz boasted afterwards that his country, a laggard in defence spending, would build "the largest conventional army within the NATO framework in Europe".
Russia's invasion, he said, had convinced Berlin "that we should spend more... an average of around 70 to 80 billion euros a year on defence over the next few years".
NATO member Bulgaria announced it would expel 70 staff from Russia's diplomatic mission accused of working against its interests.
At the G7 summit, the leaders agreed to impose new sanctions targeting Moscow's defence industry, raising tariffs and banning gold imports from the country.
The US Treasury said the measures "strike at the heart of Russia's ability to develop and deploy weapons and technology used for Vladimir Putin's brutal war of aggression against Ukraine,"
The new set of sanctions target Rostec, Russia's largest defence conglomerate, as well as military units and officers implicated in human rights abuses in Ukraine, the Treasury said.
Putin's Kremlin was not fazed by the sanctions, warning that Ukraine's forces' only option was to lay down their arms.
"The Ukrainian side can stop everything before the end of today," Kremlin spokesman Dmitry Peskov said.
"An order for the nationalist units to lay down their arms is necessary," he said, adding Kyiv had to fulfil a list of Moscow's demands.
'Everything burned'
Ukrainian President Volodymyr Zelensky called for the United Nations to visit the site of a missile strike on a shopping mall in the central city of Kremenchuk, as he addressed the UN Security Council on Tuesday.
"I suggest the United Nations send either a special representative, or the secretary-general of the United Nations, or a plenipotentiary commission to the site of this terrorist act... so the UN could independently find out information and see that this indeed was a Russian missile strike," Zelensky said of the attack on Monday that killed at least 18 people.
"Everything burned, really everything, like a spark to a touchpaper. I heard people screaming. It was horror," witness Polina Puchintseva told AFP.
All that was left of the mall was charred debris, chunks of blackened walls and lettering from a smashed store front.
Russia claims its missile salvo was aimed at an arms depot -- but none of the civilians who talked to AFP knew of any weapons store in the neighbourhood.
And, outside Russia, the latest carnage sparked only Ukrainian fury and western solidarity.
"Indiscriminate attacks on innocent civilians constitute a war crime," the G7 leaders said in a statement, condemning the "abominable attack".
Zelensky declared on his social media channels: "Only total insane terrorists, who should have no place on Earth, can strike missiles at civilian objects.
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"Russia must be recognised as a state sponsor of terrorism. The world can and therefore must stop Russian terror," he added.
The G7 leaders did not go so far as to brand Putin a terrorist -- but they vowed that Russia, already under tough sanctions, would face more economic pain.
"The G7 stands united in its support for Ukraine," Scholz told reporters.
"We will continue to keep up and drive up the economic and political costs of this war for President Putin and his regime."
Oil price cap?
The G7 had announced several new measures to put the squeeze on Putin, including a plan to work towards a price cap on Russian oil.
The group also agreed to impose an import ban on Russian gold. At the same time, the G7 powers heaped financial support on Ukraine, with aid now reaching $29.5 billion.
Meanwhile, with fierce artillery duels continuing in the eastern Donbas region, Ukrainian officials said the central city of Dnipro and several other sites had been hit by more Russian missiles.
ALSO READ: G7 vows to drive up costs for Russia over Ukraine war
Pro-Moscow forces detained Igor Kolykhayev, the elected mayor of the southern Ukrainian city of Kherson.
Russian media said the "nationalist" was an opponent of Moscow's supposed efforts to "de-Nazify" Ukraine, but Kolykhayev's aides said he had been "kidnapped" by the city's illegitimate occupiers.
The UN said 6.2 million people are now estimated to have been displaced within Ukraine, in addition to 5.26 million who have fled abroad.
"Ukraine now faces a brutality which we haven't seen in Europe since the Second World War," Stoltenberg said as leaders began to gather in Madrid.
