Hundreds of civilians are thought to remain in the besieged mill, despite this weekend's evacuations.
ADVERTISEMENTUkraine is hoping to evacuate the remaining civilians in Mariupol's steelworks, after 100 people were brought to safety over the weekend.
A Sunday evacuation allowed for more than 100 civilians to be evacuated from the besieged Azovstal steel plant, where Ukrainian fighters are mounting their last resistance to Russian forces.
However, Ukrainian Deputy Prime Minister said "hundreds" remain stranded in the plant in the country's southeastern city.
Ukraine wants to continue working with the United Nations and International Red Cross to evacuate more civilians from Mariupol.
A Ukrainian commander at the plant, Denys Shlega, said Russia had resumed shelling the area as soon as the first group of civilians left the plant.
He said several hundred civilians remain in the plant, alongside nearly 500 wounded soldiers and “numerous” dead bodies, adding that "small children are still in the bunkers underneath" Azovstal.
More evacuees are expected Monday evening in Zaporijjia, a Ukrainian-controlled town some 230 km (140 miles) to the northwest of the country.
But they have not yet arrived.
This weekend's evacuation was welcomed by Ukraine, as previous attempts to bring civilians trapped in Mariupol to safety have repeatedly failed.
"Today, for the first time since the beginning of the war, this vital humanitarian corridor began to function," said Ukrainian President Volodymyr Zelensky on Sunday.
"For the first time, there were two days of real ceasefire in this territory," he added.
Footage shared on Sunday by Ukrainian forces showed elderly women and mothers with small children climbing over rubble at the steel mill and boarding a bus.
Russia's defence ministry said 69 people from the Azovstal steel plant chose to be evacuated to Ukrainian-controlled territories, while 57 others "voluntarily" asked to be taken to areas captured by Moscow-backed separatists.
Authorities in Ukraine have not confirmed this data, and it cannot be independently verified. They have previously accused Russia of forcibly relocating civilians to areas it controls.
An estimated 2,000 Ukrainian fighters remain in the sprawling Soviet-era steel mill, as the Russian military still struggles to uproot them and take full control of the city.
ADVERTISEMENTOne Ukrainian officer at the plant urged international organisations to ensure the safe passage of wounded soldiers, although he recognised this might be difficult.
“There’s rubble," said Sviatoslav Palamar deputy commander of the Azov Regiment. "We have no special equipment. It’s hard for soldiers to pick up slabs weighing tons only with their arms.”
“We hear voices of people who are still alive," he added.
Since the start of the invasion, Mariupol has experienced the brutal end of conflict, with civilians under heavy bombardment and lacking secure access to food, water, medicine and electricity
ADVERTISEMENT100,000 people are estimated by the Associated Press to remain trapped in Mariupol.