The war in Ukraine targeted the country’s southern coast Saturday as Russian forces fired cruise missiles at the city of Odesa and bombarded a steel mill housing Ukrainian civilians and fighters, hoping to complete their conquest of the port of Mariupol in time for Victory Day celebrations.

However, in a sign of the unexpectedly effective defence that has sustained the fighting into its 11th week, Ukraine’s military flattened Russian positions on a Black Sea island that was captured in the war’s first days and has become a symbol of Ukrainian resistance.

Western military analysts said a Ukrainian counter-offensive was also advancing around the country’s second-largest city, Kharkiv, even as it remained a key target of Russian shelling.

The Ukrainian army said it retook control of five villages and part of a sixth near hotly contested Kharkiv.

As Russia’s Monday holiday commemorating Nazi Germany’s defeat in the Second World War approached, cities across Ukraine prepared for an expected increase in Russian attacks.

Ukrainian President Volodymyr Zelensky urged people numbed by more than 10 weeks of war to heed air raid warnings.

US secretary of state Antony Blinken said on Saturday that Mr Zelensky and his people “embody the spirit of those who prevailed during the Second World War”.

He accused Russian President Vladimir Putin of trying “to twist history to attempt to justify his unprovoked and brutal war against Ukraine”.

“As war again rages in Europe, we must increase our resolve to resist those who now seek to manipulate historical memory in order to advance their own ambitions,” Mr Blinken said in a statement issued as the US and UK marked the Allied victory in Europe 77 years ago.

The most intense battles in recent days have been in eastern Ukraine, where the two sides are entrenched in a fierce race to capture or reclaim territory.

Moscow’s offensive in eastern Ukraine has focused on claiming the industrial Donbas region, where Russia-backed separatists have been fighting since 2014 and occupy some areas.

Moscow has also sought to sweep across southern Ukraine to both cut off the country from the sea and to connect its territory to the breakaway Transnistria region of Moldova, long home to Russian troops.

But it has struggled to achieve those objectives.

On Saturday, six Russian cruise missiles fired from aircraft hit the region of Odesa, where authorities have a curfew in place until Tuesday.

Videos posted on social media showed thick black smoke rising over Odesa with sirens wailing in the background.

Satellite photos analysed by The Associated Press showed Ukraine targeting Russian-held Snake Island in a bid to impede Russia’s efforts to control the Black Sea.

A satellite image taken early Saturday by Planet Labs PBC showed what appeared to be a Serna-class landing craft against the island’s northern beach.

The image corresponds with a Ukrainian military video showing a drone striking the Russian vessel, engulfing it in flames.

Snake Island, some 20 miles off the coast, figured in a memorable incident early in the war when Ukrainian border guards stationed there defied Russian orders to surrender, purportedly using colourful language.

Against that backdrop, Ukrainian fighters made a final stand to prevent a complete takeover of Mariupol.

Securing the strategically important Sea of Azov port would give Moscow a land bridge to the Crimea Peninsula, which Russia annexed from Ukraine during a 2014 invasion.

New satellite photos analysed by the AP showed vast devastation at a sprawling seaside steel mill that is the last corner of Ukrainian resistance in the city.

Buildings at the Azovstal plant, including one under which hundreds of fighters and civilians are hiding, had large, gaping holes in the roof, according to the images shot Friday by Planet Labs PBC.

The bombardment of the steel mill intensified in recent days despite a Russian pledge for a temporary ceasefire to allow civilians inside to escape.

Russia has used mortars, artillery, truck-mounted rocket systems, aerial bombardment and shelling from sea to target the facility.

Rescuers sought to evacuate more civilians on Saturday after a week of on-and-off convoys to get people out of Mariupol.

Dozens of civilians were delivered Friday to the care of United Nations and International Committee of the Red Cross representatives, Russian and Ukrainian officials said.

The latest evacuees followed roughly 500 others who were allowed to leave the plant and other parts of the city in recent days.

Ukrainian fighters at the Azovstal mill have repeatedly refused to surrender but acknowledged Saturday using white flags to help evacuate civilians from the site.

The fighters issued a statement via social media saying both they and the Russians have used a white flag system to halt fighting in order to get civilians out.

The Ukrainian government has called on international organizations to also help evacuate the fighters defending the plant.

By Russia’s most recent estimate, roughly 2,000 Ukrainian fighters remained at the Azovstal steelworks. They have repeatedly refused to surrender.

Mr Zelensky said “influential states” were involved in efforts to rescue the soldiers, although he did not mention any by name.

“We are also working on diplomatic options to save our troops who are still at Azovstal,” he said in his nightly video address on Saturday.

While they pounded the plant, Russian forces struggled to make significant gains elsewhere nearly two and a half months into a ruinous war that has killed thousands of people, forced millions to flee Ukraine and flattened large swathes of some cities.

Kharkiv, which was the first Soviet capital in Ukraine and had a pre-war population of about 1.4 million, remained a key target of Russian shelling in the northeast.

But Western military analysts said Ukrainian forces were making progress in securing positions around the city.

In other developments, a Russian missile on Saturday destroyed a Ukrainian national museum dedicated to the life and work of an 18th-century philosopher, the local council said. It posted photographs on Facebook showing the Gregory Skovoroda museum engulfed in flames.

As an indication of his importance to Ukraine’s cultural heritage, Skovoroda’s likeness adorns a Ukrainian banknote. The museum in Skovorodynivka lies near the Russian border in the Kharkiv region where fighting has been fierce.