The evacuation of civilians from Sloviansk continued as Russian troops pressed towards the eastern Ukrainian city.

Sloviansk has been subjected to heavy bombardment in recent days as Russian forces push westwards on day 133 of the invasion.

AFP journalists saw rockets slam into Sloviansk's marketplace and surrounding streets, with firefighters scrambling to put out the resulting blazes.

Around a third of the market in Sloviansk appeared to have been destroyed, with locals coming to see what was left among the charred wreckage.

The remaining part of the market was functioning, with a trickle of shoppers coming out to buy fruit and vegetables.

Mayor Vadym Lyakh said that around 23,000 people out of 110,000 were still in Sloviansk but claimed Russia had been unable to surround the city.

"Since the beginning of hostilities, 17 residents of the community have died, 67 have been injured," he said.

"Evacuation is ongoing. We take people out every day." Many of the evacuees were taken by bus to the city of Dnipro, further west.

"The city is well fortified. Russia does not manage to advance to the city," the mayor said.

Russians push west

The eastern Donbas is mainly comprised of the Luhansk region, which Russian forces have almost entirely captured, and the Donetsk region to its southwest - the current focus of Moscow's attack and the location of Sloviansk.

The fall of Lysychansk in Lugansk on Sunday, a week after the Ukrainian army also retreated from the neighbouring city of Sievierodonetsk, has freed up Russian troops to advance west on Kramatorsk and Sloviansk - Donetsk's two largest cities still under Ukrainian control.

On Tuesday, they were first closing in on the smaller city of Siversk - which lies between Lysychansk and Sloviansk - after days of shelling there.

Donetsk governor Pavlo Kyrylenko said Russian forces killed five civilians and injured 21 in the region on Tuesday.

Luhansk governor Sergiy Gayday insisted that Russia did not control the entire Luhansk region, saying: "Fighting still keeps going in two villages."

Ukrainian President Volodymyr Zelensky said Russia was not yet thinking about peace because "they don't feel pressure of sanctions for the moment since some allies hesitate to activate sanctions".

He is pressing Western allies for upgraded anti-missile systems.

"Our priority is sky security. We count on the arrival of powerful air defence systems. It will allow women and kids to get back home," Mr Zelensky said.

A Ukrainian serviceman inspects the ruins of Lyceum building, suspected to have been destroyed after a missile strike near Kharkiv

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Two captured Russian armoured vehicles went on display in Warsaw's historic Castle Square, under the message that Ukrainians are not just defending freedom and democracy in their own country but for Europe as a whole.

The EU set out a harder focus on energy given Russia's war in Ukraine.

"We need to prepare for further disruptions of gas supply, even a complete cut-off from Russia," European Commission chief Ursula von der Leyen told the European Parliament.

The EU has launched a €300 billion plan to wean itself off Russian fossil fuel supplies.

Russia's parliament introduced harsh prison terms for calls to act against national security, and for maintaining "confidential" cooperation with foreigners and helping them to act against Russia's interests.

Rights activists fear the new legislation will be used to snuff out any last vestiges of dissent.

MEPs also approved legislation to create a patriotic youth movement, in a move reminiscent of Soviet-era youth organisations.

Meanwhile, former Russian president Dmitry Medvedev invoked the possibility of nuclear war if the International Criminal Court moves to punish Moscow for alleged crimes in Ukraine since the February 24 invasion.

"The idea to punish a country that has the largest nuclear arsenal is absurd," said Mr Medvedev, a close ally of President Vladimir Putin.

"And potentially creates a threat to the existence of mankind."