Ukraine’s president has warned Russians that continuing the invasion would exact a toll for “generations” after tens of thousands attended a nationalist event to hear a speech by President Vladimir Putin.

The remarks by President Volodymyr Zelenskyy on Saturday came after a mass rally was held in support of Russian forces in Moscow the previous night.

Noting the 200,000 people reported to have attended the rally was similar to the number of Russian forces deployed to Ukraine, Zelenskyy said Friday’s event in Moscow illustrated the high stakes of the largest ground conflict in Europe since World War II.

“Picture for yourself that in that stadium in Moscow there are 14,000 dead bodies and tens of thousands more injured and maimed,” the Ukrainian leader said. “Those are the Russian costs throughout the invasion.”

Putin lavished praise on his country’s military forces during Friday’s flag-waving rally, which took place on the anniversary of Russia’s 2014 annexation of Crimea from Ukraine. The event included patriotic songs such as “Made in the USSR”, with the opening lines “Ukraine and Crimea, Belarus and Moldova, it’s all my country”.

“We have not had unity like this for a long time,” Putin told the cheering crowd.

Taking to the stage where a sign read “For a world without Nazism”, he railed against his foes in Ukraine with a claim they are “neo-Nazis” and insisted his actions were necessary to prevent “genocide”.

The rally took place as Russia has faced heavier-than-expected losses on the battlefield and increasingly authoritarian rule at home. Russian police have detained thousands of antiwar protesters.

Fighting raged on multiple fronts in Ukraine more than three weeks after Russia’s February 24 invasion.

The northwest Kyiv suburbs of Bucha, Hostomel, Irpin and Moshchun were under fire on Saturday, the Kyiv regional administration reported. The city of Slavutich, 165km (103 miles) north of the capital, was “completely isolated”, the administration said.

In the besieged port city of Mariupol, the site of some of the war’s greatest suffering, Ukrainian and Russian forces battled over the Azovstal steel plant, one of the biggest in Europe, Vadym Denysenko, adviser to Ukraine’s interior minister, said on Saturday.

Ukrainian and Russian officials agreed to establish 10 humanitarian corridors for bringing aid in and residents out — one from Mariupol and several around Kyiv and in the eastern Luhansk region, Ukrainian Deputy Prime Minister Iryna Vereshchuk said.

She also announced plans to deliver humanitarian aid to the southern city of Kherson, which was seized by Russian forces.

‘Territorial integrity and justice’

In his nightly video address, Zelenskyy said Russian forces were blockading the largest cities with the goal of creating such miserable conditions that Ukrainians will surrender. But he warned Russia would pay the ultimate price.

“The time has come to restore territorial integrity and justice for Ukraine. Otherwise, Russia’s costs will be so high that you will not be able to rise again for several generations,” he said.

Vladimir Medinsky, who has led Russian negotiators in several rounds of talks with Ukraine, said on Friday the two sides have moved closer to an agreement on the issue of Ukraine dropping its bid to join NATO and adopting a neutral status.

In remarks carried by Russian media, he said the sides are now “halfway” on issues regarding the demilitarisation of Ukraine.

However, Mikhailo Podolyak, an adviser to Zelenskyy, alleged that Moscow’s characterisation was intended “to provoke tension in the media”.

“Our positions are unchanged. Ceasefire, withdrawal of troops & strong security guarantees with concrete formulas,” he tweeted.

Britain’s foreign minister accused Putin of using the talks as a “smokescreen” while his forces regroup. “We don’t see any serious withdrawal of Russian troops or any serious proposals on the table,” Foreign Secretary Liz Truss told The Times newspaper.

‘Not close enough’

In a phone call with Turkey’s President Recep Tayyip Erdogan, Putin laid out plans for ending the war, according to the Turkish presidential spokesman, Ibrahim Kalin.

“President Putin thinks the positions on the Donbas and Crimea are not close enough to meet President Zelenskyy. What we need is a strategic-level meeting between the two leaders. There seems to be growing consensus … We are hoping there will be more convergence on these issues, and this meeting will take place sooner than later, because we all want this war to come to an end,” Kalin told Al Jazeera.

US Defense Secretary Lloyd Austin, during a Saturday visit to NATO ally Bulgaria, said the Russian invasion had “stalled on a number of fronts” but the United States had not yet seen signs that Putin was deploying additional forces.

Major General Oleksandr Pavlyuk, who is leading the defence of the region around Kyiv, said his forces are well-positioned to defend the city.

“We will never give up. We will fight until the end. To the last breath and to the last bullet,” said Pavlyuk. (Al Jazeera: Excluding headline)

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