KYIV, Ukraine (AP) — Ukrainian fighters extracted from the last bastion of resistance in Mariupol were taken to a former penal colony in enemy-controlled territory, and a top military official hoped they could be exchanged for Russian prisoners of war. But a Moscow lawmaker said they should be brought to “justice.”

The Russian parliament planned to take up a resolution Wednesday to prevent the exchange of Azov Regiment fighters, who held out for months inside the Azovstal steelworks plant while Mariupol was under siege, according to Russian news agencies.

Ukraine's deputy defense minister, Hanna Maliar, said negotiations for the fighters' release were ongoing, as were plans to rescue fighters who are still inside the sprawling steel mill. Ukrainian President Volodymyr Zelenskyy said “the most influential international mediators are involved” in the plans. Officials have not said how many remain inside.

More than 260 Ukrainian fighters — some of them seriously wounded and taken out on stretchers — left the ruins of the Azovstal plant on Monday and turned themselves over to the Russian side in a deal negotiated by the warring parties. An additional seven buses carrying an unknown number of Ukrainian soldiers from the plant were seen arriving at a former penal colony Tuesday in the town of Olenivka, about 88 kilometers (55 miles) north of Mariupol.

While Russia called it a surrender, the Ukrainians avoided that word and instead said the plant’s garrison had successfully completed its mission to tie down Russian forces and was under new orders.

“To save their lives. Ukraine needs them. This is the main thing,” Ukrainian Defense Minister Oleksiy Reznikov said.

With the fighters' departures, Mariupol was on the verge of falling under complete Russian control. Its capture would be the biggest city to be taken by Moscow’s forces and would give the Kremlin a badly needed victory, though the landscape has largely been reduced to rubble.

The soldiers who left the plant were searched by Russian troops, loaded onto buses and taken to two towns controlled by Moscow-backed separatists. More than 50 of the fighters were seriously wounded, according to both sides.

It was impossible to confirm the total number of fighters brought to Olenivka or their legal status. While both Mariupol and Olenivka are officially part of Ukraine’s eastern Donetsk region, Olenivka has been controlled by Russia-backed separatists since 2014 and forms part of the unrecognized “Donetsk People’s Republic.” Prior to the rebel takeover, penal colony No. 120 had been a high-security facility designed to hold prisoners sentenced for serious crimes.

Footage shot by The Associated Press showed that the convoy was escorted by military vehicles bearing the pro-Kremlin “Z” sign, as Soviet flags fluttered from poles along the road. About two dozen Ukrainian fighters were seen in one of the buses.

Ukraine’s human rights ombudsman said the Russian military was also holding more than 3,000 civilians from Mariupol at another former penal colony near Olenivka. Ombudsman Lyudmyla Denisova said most civilians are held for a month, but those considered “particularly unreliable,” including former soldiers and police, are held for two months. The detainees include about 30 volunteers who delivered humanitarian supplies to Mariupol while it was under siege, she said.

While Ukraine expressed hope that the fighters would be released, Vyacheslav Volodin, speaker of the lower house of the Russian parliament, said without evidence that there were “war criminals” among the defenders and “we must do everything to bring them to justice.”

Russia’s main federal investigative body said it intends to interrogate the troops to “identify the nationalists” and determine whether they were involved in crimes against civilians. Also, Russia’s top prosecutor asked the country’s Supreme Court to designate Ukraine’s Azov Regiment a terrorist organization. The regiment has links to the far right.

The operation to abandon the steel plant and its labyrinth of tunnels and bunkers signaled the beginning of the end of a nearly three-month siege that turned Mariupol into a worldwide symbol of both defiance and suffering.

The Russian bombardment killed over 20,000 civilians, according to Ukraine, and left the remaining inhabitants — perhaps one-quarter of the southern port city's prewar population of 430,000 — with little food, water, heat or medicine.

During the siege, Russian forces launched lethal airstrikes on a maternity hospital and a theater where civilians had taken shelter. Close to 600 people may have been killed at the theater.

Gaining full control of Mariupol would give Russia an unbroken land bridge to the Crimean Peninsula, which it seized from Ukraine in 2014, and deprive Ukraine of a vital port. It could also free up Russian forces to fight elsewhere in the Donbas, the eastern industrial heartland that the Kremlin is bent on capturing.

And it would give Russia a victory after repeated setbacks on the battlefield and the diplomatic front, beginning with the abortive attempt to storm Kyiv, the capital.

The Russian victory, though, is more of a symbolic boost for Russian President Vladimir Putin than a military win, said retired French Vice Adm. Michel Olhagaray, a former head of France’s center for higher military studies. He said: “factually, Mariupol had already fallen.”

“Now Putin can claim a ‘victory’ in the Donbas,” Olhagaray said.

But because the Azovstal defenders’ “incredible resistance” tied down Russian troops, Ukraine can also claim that it came out on top.

“Both sides will be able take pride or boast about a victory — victories of different kinds,” he said.

Ukrainian presidential adviser Mykhailo Podolyak likened the Ukrainian defenders to the vastly outnumbered Spartans who held out against Persian forces in ancient Greece. “83 days of Mariupol defense will go down in history as the Thermopylae of the XXI century," he tweeted.

Both Russian and Ukrainian officials said peace talks were on hold.

Elsewhere across the Donbas, eight civilians were killed Tuesday in Russian attacks on 45 settlements in the Donetsk and Luhansk regions, the General Staff of the Ukrainian Armed Forces said.

Zelenskyy said Russian forces also fired missiles at the western Lviv region and the Sumy and Chernihiv regions in the northeast. He said the border regions of Ukraine saw Russian “sabotage activity.”

He said the assaults were “a test of our strength” and "kind of an attempt to compensate the Russian army for a series of failures in the east and south of our country.”

Ukrainian guerrilla fighters also killed several high-ranking Russian officers in the southern city of Melitopol, the regional administration said on Telegram. Russian forces have occupied the city since early in the war.

The report could not immediately be confirmed. Throughout the war, Ukraine has claimed to have killed many Russian generals and other officers. A few of the deaths have been confirmed by Russia.

Russian officials in Belgorod and Kursk — two regions bordering Ukraine — accused Kyiv of shelling villages and civilian infrastructure along the frontier, the latest in a series of similar accusations over the recent weeks.

___

McQuillan and Yuras Karmanau reported from Lviv, Ukraine. Mstyslav Chernov and Andrea Rosa in Kharkiv, Elena Becatoros in Odesa and other AP staffers around the world contributed.

___

Follow AP’s coverage of the war in Ukraine: https://apnews.com/hub/russia-ukraine

Copyright 2022 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed without permission.