Nearly 1,000 last-ditch Ukrainian fighters who had held out inside Mariupol’s pulverized steel plant have surrendered, Russian said Wednesday, as the battle that turned the city into a worldwide symbol of defiance and suffering drew toward a close.

Meanwhile, the first captured Russian soldier to be put on trial by Ukraine on war-crimes charges pleaded guilty to killing a civilian and could get life in prison. And Finland and Sweden applied to join

NATO, abandoning generations of neutrality for fear that Russian President Vladimir Putin will not stop with Ukraine.

The Ukrainian fighters trooping out of the ruined Azovstal steelworks that became the last stronghold of resistance in the city face an uncertain fate. Some were taken by the Russians to a former penal colony in territory controlled by Moscow-backed separatists.

Ukraine said it hopes to get the soldiers back in a prisoner swap, but Russia threatened to put some of them on trial for war crimes.

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It was unclear how many fighters remained inside the plant’s labyrinth of tunnels and bunkers, where 2,000 were believed to be holed up at one point. The leader of a Russia-backed separatist government that claims Mariupol as part of its territory said no top commanders had emerged from the plant.

The steel plant was the only thing standing in the way of Russia declaring the full capture of Mariupol. Its fall would make Mariupol the biggest Ukrainian city to be taken the Russians, giving a boost to Putin in a war where many of his plans have gone awry.

Military analysts, though, said the city’s capture would hold more symbolic importance than anything else, since Mariupol is already effectively under Moscow’s control and many of the Russian forces that were tied down by the fighting have already been moved out.

Russian Defense Ministry spokesman Maj. Gen. Igor Konashenkov said 959 Ukrainian troops have abandoned the stronghold since they started coming out Monday.

Video showed the fighters carrying out their wounded on stretchers and undergoing pat-down searches before being taken away on buses escorted by military vehicles bearing the pro-Kremlin “Z” sign.