At least 17 people were killed and dozens wounded Friday in missile strikes on Ukraine's Odessa region, a day after Russian troops abandoned positions on a strategic island in a major setback to the Kremlin's invasion.

The news came after NATO leaders wrapped up a summit in Madrid, with US President Joe Biden announcing $800 million in new weapons for Ukraine.

"We are going to stick with Ukraine, and all of the alliance are going to stick with Ukraine, as long as it takes to make sure they are not defeated by Russia," he said.

Charts showing NATO's military spending and personnel
Charts showing NATO's military spending and personnel AFP / Gal ROMA

Russian Foreign Minister Sergei Lavrov compared surging diplomatic tensions to the Cold War, telling reporters: "As far as an Iron Curtain is concerned, essentially it is already descending... The process has begun."

There was a glimmer of hope however, when Indonesian President Joko Widodo said he had given Russian President Vladimir Putin a message from their Ukrainian counterpart, Volodymyr Zelensky.

It came after Widodo visited both Moscow and Kyiv. Neither side has revealed what was in the note.

Genadiy, 51, was injured in a Russian missile attack on a shopping mall in Kremenchuk that NATO leaders have dubbed a 'war crime'
Genadiy, 51, was injured in a Russian missile attack on a shopping mall in Kremenchuk that NATO leaders have dubbed a 'war crime' AFP / Genya SAVILOV

Early Friday, missiles were fired at an apartment building and recreation centre about 80 kilometres (50 miles) south of the Black Sea port of Odessa, which has become a strategic flashpoint in the conflict.

The nine-storey apartment building was partially destroyed, leaving 14 people dead and 30 wounded, the emergency services said.

Three people, including a child, were killed and one wounded in the attack on the recreation centre, they said.

Ukraine's President Volodymyr Zelensky was unable to attend the NATO summit in person as he marshalls the defence of his homeland, but addressed Western leaders by videolink
Ukraine's President Volodymyr Zelensky was unable to attend the NATO summit in person as he marshalls the defence of his homeland, but addressed Western leaders by videolink AFP / GABRIEL BOUYS

The strikes, in Bilhorod-Dnistrovskyi, were launched by aircraft that flew in from the Black Sea, said Odessa military administration spokesman Sergiy Bratchuk.

"The worst case scenario played out and two strategic aircraft came to the Odessa region," he said in a TV interview, adding they had fired "very heavy and very powerful" missiles.

Earlier this week, there was global outrage when a Russian strike destroyed a shopping centre in Kremenchuk, central Ukraine, killing at least 18 civilians. Putin has denied Moscow's forces were responsible.

Ukraine has gathered the wrecked remains of Russian guns and armour as an exhibit on the streets of Kyiv
Ukraine has gathered the wrecked remains of Russian guns and armour as an exhibit on the streets of Kyiv AFP / Sergei SUPINSKY

Friday's attacks came a day after Russian troops abandoned their positions on Snake Island, off the coast of Odessa.

Russian forces have retreated from Snake Island, a Ukrainian outcrop in the Black Sea, but continue to bombard mainland targets like this factory in Kharkiv
Russian forces have retreated from Snake Island, a Ukrainian outcrop in the Black Sea, but continue to bombard mainland targets like this factory in Kharkiv AFP / SERGEY BOBOK

The island had become a symbol of Ukrainian resistance in the first days of the war, when the rocky outcrop's defenders told a Russian warship to "go f*ck yourself" after it called on them to surrender -- an incident that spurred a defiant meme.

It was also a strategic target, sitting aside shipping lanes near the port of Odessa. Russia had attempted to install missile and air defence batteries while under fire from drones.

The decision to abandon Snake Island "changes the situation in the Black Sea considerably", Zelensky said in his daily address Thursday.

Russian forces have retreated from Snake Island, a Ukrainian outcrop in the Black Sea, but continue to bombard mainland targets like this factory in Kharkiv
Russian forces have retreated from Snake Island, a Ukrainian outcrop in the Black Sea, but continue to bombard mainland targets like this factory in Kharkiv AFP / SERGEY BOBOK

"It does not yet guarantee security. It does not yet guarantee that the enemy will not return. But it already considerably limits the actions of the occupiers."

The Russian defence ministry statement described the retreat as "a gesture of goodwill" meant to demonstrate that Moscow will not interfere with UN efforts to organise protected grain exports from Ukraine.

In peacetime, Ukraine is a major agricultural exporter, but Russia's invasion has damaged farmland and seen Ukraine's ports seized, razed or blockaded -- sparking concerns about food shortages, particularly in poor countries.

Western powers have accused Putin of using the trapped harvest as a weapon to increase pressure on the international community, and Russia has been accused of stealing grain.

On Thursday, a ship carrying 7,000 tonnes of grain sailed from Ukraine's occupied port of Berdyansk, said the regional leader appointed by the Russian occupation forces.

Evgeny Balitsky, the head of the pro-Moscow administration, said Russia's Black Sea ships "are ensuring the security" of the journey, adding that the port had been de-mined.

The conflict in Ukraine dominated the NATO summit in Madrid this week, as the alliance officially invited Sweden and Finland to join, and Biden announced new deployments of US troops, ships and planes to Europe.

Russian missiles continued to rain down elsewhere in Ukraine, with the city of Lysychansk in the eastern Donbas region coming under sustained bombardment.

Capturing the city would allow the Russians to push deeper in the Donbas, which has become the focus of their offensive since failing to capture Kyiv after their February invasion.

Sergiy Gaiday -- governor of the Lugansk region, which includes Lysychansk -- said the city continued to face heavy shelling.

"Residents of Lysychansk barely leave their basements and homes," he wrote on Telegram, adding fires had broken out in houses and shopping malls.

The Russians had taken control of parts of the city's oil refinery, he said.

Ukraine was recently granted "candidate status" by the European Union as it pushes to join the bloc, although membership is likely still years away.

On Friday, the president of the European Commission Ursula von der Leyen told Ukraine's parliament that membership was "within reach" but urged them to press forward with anti-corruption reforms.

Zelensky meanwhile announced Ukraine had begun exporting electricity to the EU, via Romania, as fears grow of an energy crisis in Europe due to reduced Russian gas deliveries.