"Over the past 24 hours, 265 militants have laid down their arms and surrendered, including 51 seriously wounded," its defence ministry said on Tuesday.

Kremlin spokesman Dmitry Peskov said President Putin had guaranteed the Ukrainian fighters would be treated "in accordance with international standards".

Extraordinary 'damning' verdict of war shown on Russian TV | Ukraine live

It comes after Ukraine's military said it was working to evacuate all remaining troops from their last stronghold in the besieged port city.

It is not known how many - if any - Ukrainian fighters are still in the steelworks.

Ukraine's deputy defence minister, Hanna Malyar, earlier said those who needed medical treatment were taken to a hospital in the Russian-controlled town of Novoazovsk, about 30 miles east of Mariupol.

Others were being taken to Olenivka, about 55 miles north, through humanitarian corridors, she said, adding that they would be exchanged with Russian military prisoners before returning home.

For weeks, the soldiers were the last remaining pocket of resistance against the Russian advance in Mariupol, a strategically-important city in southern Ukraine.

Ms Malyar said: "Thanks to the defenders of Mariupol, Ukraine gained critically important time, and they fulfilled all their tasks. But it is impossible to unblock Azovstal by military means."

"We are working to save people who are still in Azovstal," she added, without saying how many people remained.

Ukraine's President Zelenskyy said on Monday night: "Thanks to the actions of the Ukrainian military, the Armed Forces of Ukraine, intelligence, as well as the negotiating team, the International Committee of the Red Cross and the UN, we hope that we will be able to save the lives of our guys.

"There are severely wounded ones among them - they're receiving care.

"I want to emphasise that Ukraine needs Ukrainian heroes alive. This is our principle. I think that every adequate person will understand these words."

Other key developments:
• Russia claims one of its missiles hit a US and European arms shipment near the Lviv region
• Finnish parliament approves NATO membership bid 188 votes to 8
• Putin appears to row back, saying Moscow does not see Finnish and Swedish membership as a direct threat in itself
• Turkey's president objects to Sweden and Finland joining over alleged support of Kurdish militants and other groups
• Russia's foreign ministry says attempts by the West and G7 to isolate Moscow has worsened global food shortages
• Russia has shelled the eastern city of Sievierodonetsk in the Donbas region, killing at least 10 people, according to the governor of the Luhansk region

On Monday, Russia announced an agreement for the injured Ukrainian soldiers to leave the steel plant for treatment in a town held by pro-Moscow separatists.

Later last night, five buses were seen leaving the steel plant with soldiers inside.

The General Staff of Ukraine's Armed Forces said on Facebook: "The supreme military command ordered the commanders of the units stationed at Azovstal to save the lives of the personnel.

"Efforts to rescue defenders who remain on the territory of Azovstal continue."

At one point it was thought there were a few thousand Ukrainian troops in the steelworks, along with a few hundred civilians, as Russian soldiers closed in.

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Read more:
The pounding of Azovstal - pictures that tell a thousand words

The Azov Regiment said that its troops in Mariupol held out for 82 days, buying time for the rest of Ukraine to fight Russian forces and secure Western weapons.

For much of that time, the soldiers in Mariupol - along with the remaining civilians - faced severe shortages of food, water, electricity, ammunition, and medicine.

Ukraine says tens of thousands of people have been killed in Mariupol, with much of the city lying in ruins.