Correction: This story has been updated to correctly reflect when the evacuation of citizens in Mariupol will recommence.

CNN  — 

The evacuation of civilians from the besieged southern Ukrainian city of Mariupol has been paused until Monday, the Mariupol City Council announced Sunday, citing “security reasons.”

The city council said in a Telegram post that the evacuation would recommence at 8 a.m. local time near a shopping center in Mariupol.

The announcement came hours after Ukrainian President Volodymyr Zelensky announced that the evacuation of civilians from the Azovstal steel plant in Mariupol was underway.

Zelensky said later Sunday that for the first time, the vital corridor to evacuate civilians from the plant had started working, adding that more than 100 civilians had been evacuated.

After the evacuation of those civilians, the steel plant came under fire again Sunday night, according to a Ukrainian soldier in Mariupol who spoke to Ukrainian television.

“The occupiers began firing on Azovstal again as soon as the evacuation of some Ukrainians was completed,” said Denis Schlega, commander of the 12th brigade of Ukraine’s National Guard. Schlega claimed they were using “all kinds of weapons.”

It was unclear Sunday evening whether the renewed shelling would jeopardize the next stage of the evacuation from the steel plant.

Hundreds of people – dozens of whom are injured – are thought to be inside the complex, the last Ukrainian holdout in the city following weeks of heavy Russian bombardment.

Ukraine’s Deputy Prime Minister Iryna Vereshchuk said, “The situation has become a sign of a real humanitarian catastrophe, because people are running out of water, food and medicine.”

Nearly every building on the plant has been destroyed, new satellite images showed Saturday.

An estimated 100,000 people remain in the city, officials have said.

Earlier Sunday, Zelensky tweeted that the evacuation of civilians from the steel plant had begun.

“The 1st group of about 100 people is already heading to the controlled area. Tomorrow we’ll meet them in Zaporizhzhia. Grateful to our team! Now they, together with #UN, are working on the evacuation of other civilians from the plant,” the Ukrainian President said.

The evacuation’s commencement was confirmed by the International Committee of the Red Cross, who said it would be working with the United Nations on the operation.

A convoy set off on Friday, traveling 230 kilometers to reach Mariupol on Saturday morning, the ICRC said in a statement.

“The ICRC insists on the fact that no details can be shared until the situation allows, as it could seriously jeopardize the safety of the civilians and the convoy. Relevant local authorities are communicating with the civilians about practical details,” the statement added.

The Russian news agency TASS, citing the Ministry of Defense in Moscow, reported that 80 civilians were rescued from the “territory” of the Azovstal plant and evacuated to a Russian-controlled compound a few miles away.

It’s unclear whether any of them came from within the plant itself.

“Civilians evacuated by Russian servicemen from the Azovstal plant, who wished to leave for areas controlled by the Kiev regime, were handed over to representatives of the UN and the International Committee of the Red Cross,” the ministry said.

Russian Foreign Minister Sergey Lavrov said in an interview on Italian television Sunday that the “Kyiv authorities are trying by all means to achieve the withdrawal of the Ukrainian radicals remaining in Azovstal, since among them there may be western officers and mercenaries.”

There’s been no firm evidence that western nationals are among the fighters at Azovstal.

Lavrov said: “The situation with the confrontation at the Azovstal plant in Mariupol and the stubborn, even hysterical desire of Zelensky, his team and his Western patrons to achieve the withdrawal of all these people and send them to the territory of Ukraine is explained by the fact that there are many characters who will confirm the presence of mercenaries and, perhaps, active officers of the Western armies on the side of the Ukrainian radicals.”

‘We pray that everything works’

Earlier Sunday, the Mariupol city council had urged civilians to gather near a shopping center as there was a “chance” of an evacuation corridor to Zaporizhzhia from the besieged city.

“If you have relatives or acquaintances in Mariupol, try to contact them by all ways. Call, text and say that it is possible to go to Zaporozhzhia, where it is safe,” the Council said on Telegram, instructing civilians to meet around “Port City” shopping center at 4 p.m.

“We pray that everything works,” it added.

The evacuation’s launch came a day after two groups of civilians were evacuated from the vicinity of the Azovstal plant, according to Russian state news agencies.

A total of 46 people had left “residential buildings adjacent to Azovstal” and “were provided with accommodation and food,” TASS and RIA Novosti said, quoting the Russian Ministry of Defense.

The Russian agencies did not disclose where the evacuees were being taken.

Earlier Sunday, a Ukrainian commander inside the plant said some civilians had been evacuated from the plant Saturday following the introduction of a ceasefire.

Capt. Svyatoslav Palamar, the deputy commander of the Azov Regiment, said the ceasefire, which was supposed to begin at 6 a.m., ended up starting at 11 a.m.

Palamar said 20 women and children had been taken to the “agreed meeting point,” in the hope that they would be evacuated to the “agreed destination” of Zaporizhzhia.

This story has been updated with additional information Sunday.