STORY: They were seen arriving on buses in the Russian-controlled town of Olenivka near Donetsk.
The full abandonment of the bunkers and tunnels of the bombed-out plant by the Azov Regiment means an end to the most destructive siege of a war that began when Russia invaded Ukraine nearly three months ago.
"The territory of the Azovstal metallurgical plant... has been completely liberated," the ministry said in a statement. It said the group that had surrendered comprised 531 people.
Moscow calls the Azov Regiment "Nazis". The unit, formed in 2014 as a militia to fight Russian-backed separatists, denies being fascist, and Ukraine says it has been reformed from its radical nationalist origins.
"The underground facilities of the enterprise, where the militants were hiding, came under the full control of the Russian armed forces," said the Russian statement, adding that a total of 2,439 defenders had surrendered in the past few days.
Ukraine ordered the troops to stand down on Monday (May 16). Hours before the Russian announcement, President Volodymyr Zelenskiy said the defenders had been told by Ukraine's military that they could get out and save their lives.
Kyiv calls the defenders heroes, saying their dogged stand helped tie down Russian forces and allow Ukraine to succeed elsewhere on the battlefield.