The Kremlin portrayed the pullout from Snake Island as a ``goodwill gesture.'' Ukraine's military said the Russians fled in two small speedboats following a barrage of Ukrainian artillery and missile strikes. The exact number of troops was not disclosed.

Russian Defense Ministry spokesman Lt. Gen. Igor Konashenkov said the withdrawal was intended to demonstrate that Moscow isn't hampering U.N. efforts to establish a humanitarian corridor for exporting agricultural products from Ukraine.

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

Turkey has sought to broker a deal to unblock grain exports. But the talks have dragged on, with Kyiv expressing fear that Russia will exploit the removal of the mines to attack Odesa.

Snake Island sits along a busy shipping lane. Russia took control of it in the opening days of the war in the apparent hope of using it as a staging ground for an assault on Odesa.

It was unclear if the evacuation meant a change in Moscow's designs on Odesa. Odesa is Ukraine's biggest port, crucial for shipping grain to Africa, the Middle East and other parts of the world, and is also the headquarters of the country's navy.

The island early on took on legendary significance for Ukraine's resistance to the Russian invasion, when Ukrainian troops there reportedly received a demand from a Russian warship to surrender or be bombed. The answer supposedly came back, ``Go (expletive) yourself.''

Ukraine has celebrated the story with patriotic fervor, issuing a postage stamp in commemoration.

The island's Ukrainian defenders were captured by the Russians but later freed as part of a prisoner exchange. After the island was taken, the Ukrainian military heavily bombarded the small Russian garrison there and its air defenses.

At a NATO summit in Madrid, British Prime Minister Boris Johnson billed the Russian pullout as a sign that Ukraine will prevail in the war launched by Russian President Vladimir Putin. ``In the end it will prove impossible for Putin to hold down a country that will not accept'' occupation, Johnson said.

Meanwhile, Moscow kept up its push to take control of the entire Donbas region in eastern Ukraine. It is focused on the city of Lysychansk, the last remaining Ukrainian stronghold in 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 Donbas.

Ukraine said the Russians were shelling Lysychansk and clashing with Ukrainian defenders around an oil refinery on the edge of the city.

Luhansk Gov. Serhiy Haidai said Russian reconnaissance units tried to enter Lysychansk on Wednesday but were repelled. 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,'' Haidai said.