"This part of the Mariupol humanitarian operation is over," Deputy Prime Minister Iryna Vereshchuk wrote on the Telegram messaging app on Saturday.
The Soviet-era steel mill, the last holdout in Mariupol for Ukrainian forces, has emerged as a symbol of resistance to the wider Russian effort to capture swathes of eastern and southern Ukraine.
Under heavy bombardment, fighters and civilians have been trapped for weeks in deep bunkers and tunnels that criss-cross the site.
Russian forces backed by tanks and artillery tried again on Saturday to storm Azovstal, Ukraine's military command said, part of a ferocious assault to dislodge the last Ukrainian defenders in the strategic port city on the Azov Sea.
Mariupol has been left in ruins by weeks of Russian bombardment. Several groups of civilians have left the sprawling steel complex during pauses in fighting over the past week.
Earlier on Saturday, Russia's Interfax news agency cited Moscow-backed separatists in Ukraine's Donetsk region as saying that 50 more people had been evacuated from the besieged steelworks.
However, by the afternoon, Reuters journalists had not seen any sign of their arrival at a reception centre in separatist-controlled territory near Mariupol.
The separatists said a total of 176 civilians had now been evacuated from the plant.
Evacuations of civilians from the Azovstal plant - brokered by the United Nations and the International Committee of the Red Cross (ICRC) - began last weekend. But they were halted during the week by renewed fighting.
The city's mayor estimated earlier this week that 200 civilians were trapped at the plant.
It was not clear after the deputy prime minister's statement on Saturday if civilian men were still in the complex.
President Volodymyr Zelenskiy said in a late-night video address on Friday that Ukraine was also working on a diplomatic effort to save fighters barricaded inside the steel works. It was unclear how many fighters remained there.
The fighters have vowed not to surrender. Ukrainian officials fear Russian forces want to wipe them out by Monday, in time for Moscow's commemorations of the Soviet Union's victory over Nazi Germany in World War Two.
President Vladimir Putin declared victory in Mariupol on April 21, ordered the plant sealed off and called for Ukrainian forces inside to disarm. But Russia later resumed its assault on the plant.
Asked about plans for Russia to mark Monday's anniversary in parts of Ukraine it holds, Kremlin spokesperson Dmitry Peskov said on Friday "The time will come to mark Victory Day in Mariupol."
