All vulnerable civilians have been evacuated from the Azovstal steelworks holdout in Mariupol, Ukraine said Saturday, presaging a showdown between Kyiv's last remaining soldiers there and the besieging Russian forces ahead of celebrations marking the Soviet World War II victory.
The steel mill, the final pocket of Ukrainian resistance in the devastated port city, has taken on a symbolic value in the war. Kyiv fears a renewed intensity to Moscow's offensive.
During a speech, Ukrainian President Volodymyr Zelensky said that hundreds of people had been removed from the plant and that preparations for a second stage of evacuation comprising the wounded and medics were under way.
Fighting continues on many fronts, and Ukraine's defence ministry said it had destroyed another Russian vessel -- a Serna-class landing craft -- in the Black Sea.
"The traditional parade of the Russian Black Sea fleet on May 9 this year will be held near Snake Island -- at the bottom of the sea," the ministry added. Russia did not immediately confirm the incident.
Earlier, Ukraine's defence ministry said Russian forces had resumed their assault on the Azovstal site, despite talk of a truce to allow trapped civilians to flee.
- Putin may be 'doubling down' -
According to Russia's defence ministry, 77 aircraft will conduct a fly-past, including the rarely seen Il-80 Doomsday plane that can withstand a nuclear attack.
Despite apocalyptic nuclear threats carried by Russian state media, the CIA said Saturday it saw no indication Moscow was preparing to use tactical atomic weapons in the Ukraine conflict.
"We don't see, as an intelligence community, practical evidence at this point of Russian planning for the deployment or even potential use of tactical nuclear weapons," CIA director Bill Burns said at a conference.
Burns also warned that Putin believed he could not afford defeat in Ukraine and that he might be "doubling down" on the offensive.
Eight Mig-29 fighter jets will fly over Moscow's Red Square during Monday's festivities, forming the letter "Z" -- the mark of Russia's military assault in Ukraine.
The Russian campaign has run into tough resistance -- and galvanised Kyiv's western allies to comprehensively sanction the Russian economy and Putin's inner circle.
But with Victory Day approaching, Ukrainian officials fear more intense missile and artillery bombardments and renewed assaults, as Moscow scrambles for symbolic wins.
- 'Massive bombardments' -
The Ukrainian rescue service said a missile had hit a technical college in Kostiantynivka, in the eastern region of Donetsk, killing at least two people.
Donetsk regional governor Pavlo Kyrylenko reported "massive bombardments" along the frontline.
Four civilians had been killed in Donetsk, two in Bakhmut and two in Kostiantynivka, with another nine people wounded, he added.
Ukrainian forces, meanwhile, have launched a counter-offensive.
According to the defence ministry, Russian troops were forced to demolish three road bridges near Tsyrkuny and Ruski Tyshky outside Kharkiv, to slow the Ukrainian advance.
Zelensky said Saturday that a Russian missile has struck a museum in the Kharkiv region, announcing that the "Russian army destroyed or damaged nearly 200 cultural heritage sites already."
British intelligence said Ukrainian forces equipped with high-end weaponry by western allies have been able to destroy at least one of Russia's most advanced tanks, the T-90M.
"The conflict in Ukraine is taking a heavy toll on some of Russia's most capable units and most advanced capabilities," UK Defence Intelligence said.
"It will take considerable time and expense for Russia to reconstitute its armed forces following this conflict," it said, adding that sanctions on advanced components would make it harder for Russia to re-arm.
- Western aid -
G7 leaders, including US President Joe Biden, and Ukraine's Zelensky will on Sunday discuss Western support for Kyiv in videoconference, after Biden on Friday announced a $150-million package of military aid.
Biden's wife, First lady Jill Biden, was in Romania Saturday meeting Ukrainian refugees.
After listening to mothers and children recount how they fled Russia's invasion of their country, she told them: "We stand with you, I hope you know that."
Ambassadors from EU member states meet in Brussels Sunday to discuss their sixth round of economic sanctions against Moscow, which this time should include a phased ban on imports of Russian oil.
- Russia to remain 'forever' -
The last Ukrainian soldiers in the devastated Black Sea port of Mariupol are believed to be holed up in the tunnels and bunkers beneath Azovstal.
Ukraine's Azov battalion, leading the defence at steelworks, said one Ukrainian fighter had been killed and six wounded when Russian forces opened fire during an earlier attempt to evacuate people by car.
Taking full control of Mariupol would allow Moscow to create a land bridge between the Crimea peninsula, which it annexed in 2014, and separatist regions run by Russian puppets in the east.
In Lugansk, Ukrainian officials said Friday that Russian forces had almost encircled Severodonetsk -- the easternmost city still held by Kyiv -- and were trying to storm it.
Kherson in the south remains the only significant city Russia has managed to capture since the war began.
A senior official from the Russian parliament, Andrey Turchak, said during a visit to the city on Friday that Russia would remain in southern Ukraine "forever".