Officials in the Ukrainian port city of Mariupol, which is surrounded by Russian forces, said they were delaying an evacuation of the civilian population, accusing Moscow's troops of breaking a ceasefire.
"Due to the fact that the Russian side does not adhere to the ceasefire and has continued shelling both of Mariupol itself and its environs and for security reasons, the evacuation of the civilian population has been postponed," city officials said in a statement on social media.
The statement came just hours after the Russian defence ministry, according to Russia's RIA news agency, said its units had opened humanitarian corridors near the cities of Mariupol and Volnovakha, which were encircled by its troops.
In Mariupol, citizens would be allowed to leave during a five-hour window, it quoted the city's officials as saying, as Russia's invasion of Ukraine entered into its 10th day.
The southeastern port city has come under heavy bombardment, a sign of its strategic value to Moscow due to its position between Russian-backed separatist territory in east Ukraine and the Crimean peninsula, which Moscow seized from Ukraine in 2014.
"This night the shelling was harder and closer," a staff member from Doctors without Borders/Medecins sans Frontieres (MSF) said, according to the aid agency, adding there was still no power, water, heating or mobile phone links and food was scarce.
The Ukrainian government said the plan was to evacuate around 200,000 people from Mariupol and 15,000 from Volnovakha, and the Red Cross is the ceasefire's guarantor.
There was no immediate confirmation that firing had stopped and it was not clear if the ceasefire would be extended to other areas, as Russia's invasion of Ukraine entered into its 10th day.
The Russian defence ministry said a broad offensive would continue in Ukraine, RIA said.
The Mariupol city council said in a statement that civilians will be able to proceed towards the city of Zaporizhzhia and will be able to use specially arranged bus routes as well as their own cars.
"A huge request to all drivers leaving the city, to contribute as much as possible to the evacuation of the civilian population — take people with you, fill vehicles as much as possible," the statement said.
In the statement, city officials told residents leaving in private vehicles that it was "strictly prohibited" to go off course from the evacuation routes.
The announcement said the evacuation would last over several days to allow the entirety of the civilian population to exit the city.
Saturday's evacuation will be the first of several stages, it said.
Earlier on Saturday, Mariupol's mayor Vadim Boychenko said that the city was under "blockade" by Russian forces after days of "ruthless" attacks.
"We are simply being destroyed," he said in a televised appeal, describing indiscriminate shelling of residential areas and hospitals.
"They want to wipe Mariupol and Mariupol residents off the face of the earth," he said in a shaky video feed that cut in and out.
While laying siege to Mariupol for days, Russian forces have cut its electricity, food, water, heating and transportation in the depths of winter, prompting comparisons to the Nazi blockade of Leningrad in World War II.
Ukraine says Russian forces have focussed efforts on encircling Kyiv and Kharkiv, the second-biggest city, while aiming to establish a land bridge to Crimea.
Kyiv, in the path of a Russian armoured column that has been stalled outside the Ukrainian capital for days, was again under attack, with explosions audible from the city centre.
Ukrainian media outlet Suspilne cited authorities in Sumy, about 300 kilometres east of Kyiv, as saying that there is a risk of fighting in the city's streets, urging residents to stay in shelters.
Russia calls its actions in Ukraine a "special operation" that it says is not designed to occupy territory but to destroy its southern neighbour's military capabilities and capture what it regards as dangerous nationalists. It denies targeting civilians.
Moscow has seized two key cities in its 10-day-long invasion, Berdiansk and Kherson on Ukraine's southern Black Sea coast.
But capturing Mariupol would represent a bigger prize for Russian forces as it would deal a severe blow to Ukraine's maritime access and connect troops coming from annexed Crimea and the Donbas.
Serhii, father of teenager Iliya, cries on his son's lifeless body lying on a stretcher at a maternity hospital converted into a medical ward in Mariupol, Ukraine, on Wednesday 2 March 2022. Source: AAP / Evgeniy Maloletka/AP
Kremlin spokesperson Dmitry Peskov said late on Friday that Moscow was waiting for a third round of talks with Ukraine in Belarus, and one of Kyiv's negotiators said it hoped to hold them this weekend.
"The third leg could take place tomorrow or the day after, we are in constant contact," Ukrainian presidential advisor Mykhailo Podolyak said Friday.
As Russia bombed cities across the country, the Ukrainian military said on Facebook that Moscow's main focus was to encircle Kyiv.
'Mariupol cannot be lost'
Ukrainian troops are holding the line against the attempted Russian advance on Mariupol, but need significant back-up, said a deputy commander of the Azov military unit, part of Ukraine's National Guard.
"This is the last city that prevents the creation of a land corridor from Russia to Crimea," he said in a post on Azov's official Telegram page, identifying himself by his call sign Kalyna.
"Mariupol cannot be lost."
Medical workers tend to women who gave birth in a basement of a maternity hospital converted into a medical ward and used as a bomb shelter in Mariupol, Ukraine, on Tuesday 1 March 2022. Source: AAP / Evgeniy Maloletka/AP
Some Mariupol residents have fled to the city centre to escape the heaviest shelling on the outskirts, said 30-year-old entrepreneur Ivan Yermolayev, who has been sheltering in the small basement of his house in the city and queuing up for water at a local well.
"They're with their children in the centre and hearing the war getting closer," he told Reuters by online message.
"There's crying, fear, uncertainty, panic."
Volodymyr Zelenskyy slams NATO
It comes as Ukrainian President Volodymyr Zelenskyy lashed NATO for ruling out a no-fly zone over his country saying the Western military alliance knew further Russian aggression was likely.
On Friday local time, NATO rejected Ukraine's request to impose a no-fly zone to halt Russia's bombing, but Western allies did warn President Vladimir Putin of fresh sanctions if he does not stop the war.
"Knowing that new strikes and casualties are inevitable, NATO deliberately decided not to close the sky over Ukraine," Mr Zelenskyy said in a video published by the presidency.
"We believe that the NATO countries themselves have created a narrative that the closing of the skies over Ukraine would provoke direct Russian aggression against NATO."
NATO chief Jens Stoltenberg had said the alliance would not intervene in the conflict over fears of a direct clash with Moscow that could spiral into a wider conflict.
"The only way to implement a no-fly zone is to send NATO fighter planes into Ukraine's airspace, and then impose that no-fly zone by shooting down Russian planes," Mr Stoltenberg said after the urgent meeting.
"If we did that, we'll end up with something that could end in a full-fledged war in Europe, involving many more countries and causing much more human suffering."
But Mr Zelenskyy insisted that the NATO gathering was a "weak summit, a confused summit".
"All the people who die starting today will also die because of you. Because of your weakness, because of your disconnection," he said.
"Today the leadership of the alliance gave the green light for further bombing of Ukrainian cities and villages, refusing to make a no-fly zone."
