Kyiv (AFP) - Thousands of Ukrainians sought to escape the hellish siege of Mariupol on Tuesday, as Russia pounded the city with bombs and UN chief Antonio Guterres appealed for Moscow to end its "unwinnable" war.
The strategic port on the Azov sea has suffered relentless shelling but Ukrainian officials say it has not yet been captured as Russia's invasion, which began almost a month ago, splutters to a halt.
People who had managed to escape Mariupol described it as a "freezing hellscape riddled with dead bodies and destroyed buildings", according to Human Rights Watch.
Ukrainian President Volodymyr Zelensky said in his regular evening address that one group fleeing along an agreed humanitarian route were "simply captured by the occupiers."
"There are about 100,000 people in the city -- in inhumane conditions, in a complete blockade, no food, no water, no medicine, under constant shelling," he said.
As US President Joe Biden readied for a trip to Europe this week to tackle a crisis that risks spiralling into global conflict, United Nations chief Antonio Guterres called for Russia to end its "absurd war."
"Even if Mariupol falls, Ukraine cannot be conquered city by city, street by street, house by house," he said.
"This war is unwinnable. Sooner or later, it will have to move from the battlefield to the peace table.That is inevitable."
'We live here'
With the Russian offensive stalled, Biden has warned that President Vladimir Putin was considering using chemical and biological weapons.
Officials in Washington said Tuesday that Ukraine forces have even reversed battlefield momentum and reclaimed some ground in recent days, particularly in the south of the country.
Russian troops were running out of supplies, and the military was beset by communication problems, even reduced to using mobile phones, Pentagon spokesman John Kirby said.
The assessment was corroborated by Ukraine's army command which said Russian troops now had ammunition, food and fuel to last just three days.
In the southern city of Mykolaiv, one bulwark of the fierce fightback, residents said they were determined to stay and defend it despite incessant bombardment.
At the burial of soldier Igor Dundukov, 46, his brother Sergei wept as he kissed his sibling's swollen, blood-stained face.
"We supported his commitment to defending our homeland," Sergei told AFP."This is our land.We live here.Where would we run to?We grew up here."
The Ukrainian army said on Facebook that 300 Russian soldiers have defected in the north-eastern Sumy region.And even in areas Russia has captured, resistance has persisted.
In the occupied southern city of Kherson, Ukraine's leaders on Tuesday accused Russian troops of firing on unarmed protesters.
Videos posted on social media and the messaging app Telegram showed citizens gathering in Kherson's "Freedom Square" protesting against Russia's recent seizure of the city.
Russian soldiers could be seen firing into the air.
Ukraine's foreign ministry said in a statement that the situation was rapidly deteriorating in Kherson, accusing Moscow of refusing to allow for an aid corridor to evacuate civilians and channel in food.
Biden is due to travel to Brussels on Thursday for a series of summits gathering NATO, EU and G7 leaders, before heading to Poland, which has received the bulk of more than 3.5 million Ukrainians fleeing war in their country.
The two sides are holding negotiations remotely after talks between delegations meeting on the border of Belarus and Ukraine made little progress.
Zelensky said all issues would be on the table if Putin agreed to direct talks, including the contested eastern region of Donbas and the annexed Crimea peninsula.
"We continue to work at various levels and to push Russia for peace," the Ukrainian leader said late Tuesday."It's very difficult.Sometimes scandalous.But step by step we are moving forward."
More sanctions
Since Russia launched its invasion on February 24, at least 117 children have been killed in the war, Ukraine's federal prosecutor said.
Some 548 schools have been damaged, including 72 completely destroyed.
Russia has pushed on with its assaults, in the face of unprecedented Western sanctions that have led international companies to pull out of the country.
More sanctions against Russia and tightening of existing measures will be announced Thursday when Biden meets European allies in Brussels.
Russia had given Mariupol until Monday morning to surrender, but Kyiv rejected the ultimatum and said the city's resistance was bolstering the defence of all of Ukraine.
Mariupol is a pivotal target in Putin's war -- providing a land bridge between Russian forces in Crimea to the southwest and Russian-controlled territory to the north and east.
Kyiv regroups
In the capital Kyiv, a 35-hour curfew came into effect from Monday evening after Russian strikes laid waste to the Retroville shopping complex, killing at least eight people.
Russia claimed the mall was being used to store rocket systems and ammunition.
With businesses closed and residents told to stay home, Kyiv was a ghost town Tuesday, with air sirens and the distant sound of explosions regularly punching through the silence.
Maxim Kostetskyi, 29, a lawyer, said residents were using the "pause" imposed by the lockdown to regroup.
"We don't know if the Russians will continue with their efforts to encircle the city, but we are much more confident, the morale is high and inspiring," he told AFP.
