Ukrainian servicemen from the Azovstal steel plant sit on a bus near a penal colony, in Olyonivka, in territory under the government of the Donetsk People's Republic, on Friday.

Ukrainian servicemen from the Azovstal steel plant sit on a bus near a penal colony, in Olyonivka, in territory under the government of the Donetsk People's Republic, on Friday. / AP

Updated May 20, 2022 at 9:29 AM ET

Russia is consolidating its control of the strategic Ukrainian city of Mariupol, after months of bombardment that Ukrainian officials say killed tens of thousands of civilians.

The battle for Mariupol has centered on the Azovstal steel plant in recent weeks. An estimated 2,000 Ukrainian fighters and several hundred civilians had been sheltering in the massive complex's underground maze of tunnels and bunkers, trapped inside for months with a dwindling supply of food, water and medical supplies.

Ukrainian officials announced earlier this month that all women, children and elderly people had been evacuated from the steel plant, as Russian attacks intensified. But the fighters defending the plant vowed never to surrender, even as their loved ones and international onlookers pleaded for their safe evacuation.

That changed on Monday, when Ukraine formally ended its combat mission in Mariupol. Hundreds of soldiers were evacuated to Russian-held territory in the eastern part of the country, with help from the United Nations and other organizations.

Russia's defense ministry said Thursday that some 1,730 Ukrainian soldiers had surrendered at the besieged steel plant, though Ukrainian officials have not confirmed that number or shared any information about the plant in recent days.

The International Committee of the Red Cross says it's registered hundreds of Azovstal defenders, including the wounded, as prisoners of war this week. That involves obtaining certain personal information in order to "track those who have been captured and help them keep in touch with their families."

The fate of the evacuated soldiers remains uncertain. Ukrainian officials said earlier this week that they would bring them home as part of a prisoner exchange, but have since gone silent.

Meanwhile, some Russian politicians are calling for them to be put on trial and even face possible execution, even though the Geneva Conventions state that combatants can't be put on trial just for participating in battle.

Plus, there could be more Ukrainian soldiers still barricaded beneath the plant, as one of its defenders indicated in a cryptic video on Thursday night.

Sviatoslav Palamar, the deputy head of the Azov Regiment, released an 18-second video in which he said that he and other Ukrainian soldiers were still inside the plant – a claim that, while unverified, suggests the story isn't over.

"There is some operation underway," he said, according to an NPR translation. "I won't go into details of that."

Winning Mariupol is a rare but major victory for Russia, and not just because of its symbolic value. Mariupol secures a link between Crimea and the Russian border and gives Russia control over the entire north shore of the Sea of Azov.

Russian media reports suggest the Kremlin is taking steps to secure its hold over southeastern Ukraine, though it's not yet clear what that might look like.

It's already installed proxies to serve as local politicians, a sign that it aims to stay put for the long-haul even as Ukrainian forces have pushed Russia back in other parts of the country.

Joanna Kakissis reported from Kyiv, Ukraine.

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Tags: azovstal steel plant  Mariupol  Russia Ukraine