Russian Defense Minister Sergei Shoigu reported to President Vladimir Putin the “complete liberation” of the Azovstal steel plant in Mariupol — the last stronghold of Ukrainian resistance — and the city as a whole, spokesman Igor Konashenkov said Friday.

There was no immediate confirmation from Ukraine.

Russia’s state news agency RIA Novosti quoted the ministry as saying a total of 2,439 Ukrainian fighters who had been holed up at the steelworks had surrendered since Monday, including over 500 on Friday.

As they surrendered, the troops were taken prisoner by the Russians, and at least some were taken to a former penal colony. Others were said to be hospitalized.

The defense of the steel mill had been led by Ukraine’s Azov Regiment, whose far-right origins have been seized on by the Kremlin as part of an effort to cast its invasion as a battle against Nazi influence in Ukraine. Russia said the Azov commander was taken away from the plant in an armored vehicle.

Russian authorities have threatened to investigate some of the steel mill's defenders for war crimes and put them on trial, branding them “Nazis” and criminals. That has stirred international fears about their fate.

The steelworks, which sprawled across 11 square kilometers (4 square miles), had been the site of fierce fighting for weeks. The dwindling group of outgunned fighters had held out, drawing Russian airstrikes, artillery and tank fire, before their government ordered them to abandon the plant's defense and save themselves.

The complete takeover of Mariupol gives Putin a badly needed victory in the war he began on Feb. 24 — a conflict that was supposed to have been a lightning conquest for the Kremlin but instead has seen the failure to take the capital of Kyiv, a pullback of forces to refocus on eastern Ukraine, and the sinking of the flagship of Russia's Black Sea fleet.