Russia on Thursday pulled back its forces from Ukraine's Snake Island, a strategic Black Sea outpost where they have faced relentless Ukrainian attacks, as it maintained its assault on the eastern province of Luhansk.

Russia's Defense Ministry said it withdrew its forces from the Zmiyinyy (Snake) Island off Ukraine's Black Sea port of Odessa in what it described as a "goodwill gesture." Ukraine's military said the Russians fled the island in two speedboats following a barrage of Ukrainian artillery and missile strikes.

Russian Defense Ministry spokesperson Lt. Gen. Igor Konashenkov insisted that the withdrawal was intended to demonstrate that "the Russian Federation wasn't hampering the United Nations' efforts to establish a humanitarian corridor for taking agricultural products from the territory of Ukraine."

Ukraine and the West have accused Russia of blockading Ukrainian ports to prevent the exports of grain, contributing to the global food crisis. Russia has denied the accusations and charged that Ukraine needs to remove sea mines from the Black Sea to allow safe navigation.

Russia took control of the island that sits on a busy shipping lane in the opening days of the war in an apparent hope to use it to control the area and use it as a staging ground for an attack on Odessa.

The island came to epitomize the Ukrainian resistance to the Russian invasion when Ukrainian troops there received a demand from a Russian warship to surrender or face bombardment. "Russian warship," the answer came back, "go (expletive) yourself."

The Ukrainian defenders of the island were captured by the Russians but later freed as part of a prisoner exchange.

Since the island was taken, the Ukrainian military has relentlessly bombarded a small Russian garrison and air defense assets stationed there.

In the east of Ukraine on Thursday, Moscow kept up its push to take control of the entire Donbass region. It is focused on the city of Lysychansk, the last remaining Ukrainian stronghold in the Luhansk province. Russian troops and their separatist allies control 95% of Luhansk and about half of Donetsk, the two provinces that make up the mostly Russian-speaking Donbass.

The Ukrainian General Staff said that the Russian troops were shelling Lysychansk and clashing with Ukrainian defenders around an oil refinery on the edge of the city.

Luhansk Gov. Serhiy Gaidai said that Russian reconnaissance units tried to enter Lysychansk Wednesday, but were repelled by the Ukrainian forces. He said the Russians were trying to block a highway used to deliver supplies and fully encircle the city. "The Russians have thrown practically all their forces to seize the city," Gaidai said.

Speaking on a visit to Turkmenistan early Thursday, Russian President Vladimir Putin said his goals in Ukraine haven't changed since the start of the war. He said they were "the liberation of the Donbass, the protection of these people and the creation of conditions that would guarantee the security of Russia itself." He made no mention of his original stated goals to "demilitarize" and "denazify" Ukraine.

He denied Russia had adjusted its strategy after failing to take Kyiv in the early stage of the conflict. "As you can see, the troops are moving and reaching the marks that were set for them for a certain stage of this combat work. Everything is going according to plan," Putin said at a news conference in Turkmenistan.

Biggest prisoner swap

Ukraine on Wednesday carried out its biggest exchange of prisoners of war since Russia invaded, securing the release of 144 of its soldiers, including 95 who defended Mariupol's steelworkers, Ukraine's military intelligence agency said.

The majority of the Ukrainians were badly wounded, suffering from gunshot and shrapnel wounds, blast traumas, burns, fractured bones and amputated limbs, the agency known by the acronym GUR said in a statement on Telegram.

In central Ukraine, funerals were to be held Thursday for some of the 18 people confirmed killed by Monday's Russian missile strike on a busy shopping mall in Kremenchuk. Crews continued to search through the rubble in search of another 20 people who remain missing.

Ukrainian State Emergency Services press officer Svitlana Rybalko told The Associated Press (AP) that along with the 18 bodies, investigators found fragments of eight more bodies. It was not immediately clear whether that meant there were more victims. A number of survivors lost limbs.

After the attack on the mall, Ukrainian President Volodymyr Zelenskyy accused Russia of becoming a "terrorist" state. On Wednesday, he reproached NATO for not embracing or equipping his embattled country more fully.

He asked for more modern artillery systems and other weapons and warned the NATO leaders they either had to provide Ukraine with the help it needed to defeat Russia or "face a delayed war between Russia and yourself."

"The question is, who's next? Moldova? Or the Baltics? Or Poland? The answer is: all of them," he said.

Russia, China slam NATO

Meanwhile, NATO faced rebukes from Moscow and Beijing on Thursday after it declared Russia a "direct threat" and said China posed "serious challenges" to global stability.

Putin warned he would respond in kind if the Nordic pair allowed NATO troops and military infrastructure onto their territory. He said Russia would have to "create the same threats for the territory from which threats against us are created."

China accused the alliance of "maliciously attacking and smearing" the country. Its mission to the European Union said NATO "claims that other countries pose challenges, but it is NATO that is creating problems around the world."

While internationally much of the diplomatic focus was on the NATO summit in Madrid on Wednesday, Russian ally Syria made a surprise announcement that it had officially recognized the pro-Russian separatist regions of Luhansk and Donetsk in eastern Ukraine as independent countries, becoming only the second country to have done so. Zelenskyy later announced diplomatic ties between Kyiv and Damascus have ended.

In southern Ukraine, the death toll from Wednesday's Russian missile strike on an apartment building in Mykolaiv rose to six, according to Gov. Vitaliy Kim. Another six people were wounded. Mykolaiv is a major port and seizing it – as well as Odessa farther west – would be key to Russia's objective of cutting off Ukraine from its Black Sea coast.