Russia warned Finland and Sweden Monday they were making a "grave mistake" in their moves to join NATO as Ukraine braced for a new push by Moscow's forces in its eastern Donbas region.
The two Nordic countries are poised to jettison decades of military non-alignment due to fears of aggression from Russia, with which Finland shares a 1,300-kilometre (800-mile) border.
Helsinki officially declared its intention to join the NATO military alliance Sunday and Sweden's ruling party has also backed membership, with the issue now being debated by both countries' parliaments.
Russia, whose invasion of neighbouring Ukraine on February 24 has sparked global outrage, killed thousands and created millions of refugees, warned there would be consequences.
"This is another grave mistake with far-reaching consequences," Deputy Foreign Minister Sergei Ryabkov told reporters Monday, warning "the general level of military tensions will increase".
"They should have no illusions that we will just put up with this," he was quoted as saying by Russian news agencies.
Russia has already suspended electricity supplies to Finland, citing payment issues.
But Finnish Prime Minister Sanna Marin told lawmakers: "Our security environment has fundamentally changed.
"The only country that threatens European security, and is now openly waging a war of aggression, is Russia."
'Dead-end'
Ukraine's Western allies have sent weapons and money to help it resist Russia's forces, and NATO promised Sunday support for as long as it was needed.
German Foreign Minister Annalena Baerbock promised military assistance "for as long as Ukraine needs".
Since failing to take the capital Kyiv in the early weeks of the war, Moscow has focused on the eastern industrial region of Donbas, near the Russian border and home to pro-Russian separatists.
"We are preparing for new attempts by Russia to attack in Donbas, to somehow intensify its movement in the south of Ukraine," President Volodymyr Zelensky said in his nightly address Sunday.
But Western intelligence has predicted its campaign will stall amid heavy losses and fierce resistance.
"The occupiers still do not want to admit that they are in a dead-end and their so-called 'special operation' has already gone bankrupt," Zelensky added.
Ukrainian presidential adviser Oleksiy Arestovich told local television Sunday that Russian troops were being redeployed towards the Donbas region after withdrawing from Kharkiv.
The defence ministry later announced Ukrainian troops had regained control of territory near Kharkiv, the country's second-largest city near the Russian border, which has been under constant attack since the invasion.
They "drove out the Russians and claimed the state border", it said in a statement posted on social media alongside a video showing armed Ukrainian soldiers gathered around a yellow-and-blue-painted border post.
Some Russian forces remain to try and block the advance, and air sirens sounded in Kharkiv city in the early hours, according to the Ukrainian army.
Arestovich said the Russian troops that had been withdrawn were being sent towards Lugansk and "their task is to take Severodonetsk," the easternmost city still held by Ukraine.
"Well, something is not working for them."
Waiting it out
The fall of Severodonetsk would grant the Kremlin de facto control of Lugansk, one of two regions -- along with Donetsk -- that comprise Donbas.
But Russia's attempt to cross a river to encircle it has been repelled with heavy losses of equipment, according to Lugansk governor Sergiy Gaiday.
And Russian-occupied railway bridges leading to Severodonetsk were blown up, the Ukrainian military said on Facebook late Sunday.
Ukraine's presidency reported Monday two people were killed and nine were wounded, including a child, in shelling on a Severodonetsk hospital.
After almost three months of fighting, more than six million refugees have fled Ukraine, and another eight million have been internally displaced, according to UN agencies.
But some are trying to wait it out.
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In Lysychansk, on the other side of the river from Severodonetsk, a policeman tried in vain to evacuate Angelina Abakumova and her children.
"It is dangerous here now. Then it changes and it becomes dangerous over there. What is the point of going back and forth?" she told AFP, on her way back to her basement.
But the battles here have grown in number as the Russians try to gain control of hills overlooking a road providing Lysychansk's last link to the outside world.
"The people who sit here just think that everything will be fine," said the policeman, Viktor Levchenko, of the dozens hiding in the underground corridors and intertwining basements of one of the city's more fortified buildings.
"But unfortunately, everything is not fine."
'Behind schedule'
Russia's defence ministry claimed it had launched strikes overnight on two Ukrainian command posts and five weapons depots in the regions of Kharkiv, Donetsk and Lugansk.
But British defence chiefs said Russia's offensive in Donbas had "lost momentum".
Demoralised Russian troops had failed to make substantial gains and Moscow's battle plan was "significantly behind schedule", UK defence intelligence said.
It added Russia may have lost a third of the ground combat forces it committed in February and was "unlikely to dramatically accelerate" its advance in the next 30 days.
Ukrainian commanders say they expect a turning point in their favour by August, but Western powers have cautioned the conflict will turn into a war of attrition stretching into next year.
EU meets on oil ban
Ukraine's Western allies have levelled unprecedented economic sanctions against Moscow to punish it for the invasion, but at the same time, European nations continue to buy Russian oil and gas.
EU foreign ministers met Monday in Brussels to discuss a proposed ban on Russian oil, but Hungary is blocking the move, arguing it would hammer the Hungarian economy.
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The war is taking its toll on the continent's growth. The European Commission sharply cut its eurozone growth forecast for 2022 to 2.7 per cent, blaming skyrocketing energy prices.
Separately, French automaker Renault has handed over its Russian assets to the Russian government, marking the first major nationalisation since the onset of sanctions.
Renault controlled 68 per cent of AvtoVAZ, the largest carmaker in Russia with the country's top brand Lada, but had been under pressure to pull out of Russia following the invasion.
