KRAMATORSK, Ukraine (AFP) - Russian troops were aiming to take control of the city of Mariupol on Tuesday (April 12), part of an anticipated massive onslaught across eastern Ukraine, as defending forces tried desperately to hold them back.
Russia is believed to be trying to connect occupied Crimea with Moscow-backed separatist territories Donetsk and Luhansk in Donbass, and has laid siege to the strategically located city, once home to more than 400,000 people.
Ukrainian forces were "surrounded and blocked", tweeted Mr Myhaylo Podolyak, an official from President Volodymyr Zelensky's office.
But on Monday the Ukrainian army insisted that "the defence of Mariupol continues".
"The connection with the units of the defence forces that heroically hold the city is stable and maintained," the Land Forces of Ukraine wrote on Telegram.
In his nightly address, Mr Zelensky made another plea to his allies for more weapons to boost the defence of the city.
"We are not getting as much as we need to end this war sooner. To completely destroy the enemy on our land... in particular, to unblock Mariupol," he said.
He made a similar appeal for military assistance to South Korea's National Assembly earlier in the day, telling lawmakers Russia had "completely destroyed Mariupol and burned it to ashes".
"At least tens of thousands of Mariupol citizens must have been killed," he added.
Chemical weapons allegations
Late on Monday, Britain said it was trying to verify reports that Russia had also used chemical weapons in the city.
Western officials have previously expressed concerns that as the conflict drags into its seventh week, Russia could resort to such extreme measures.
Ukrainian lawmaker Ivanna Klympush said Russia had used an "unknown substance" and that people were suffering from respiratory failure.
But on messaging app Telegram, Mr Petro Andryushchenko, an aide to the city's mayor, wrote that a chemical attack was not confirmed and that they were "waiting for official information from the military".
Elsewhere in the east, heavy bombardment continued as civilians were urged to flee ahead of an expected Russian troop surge in the region.
Eight people were killed by shelling in the northeastern city of Kharkiv, the head of the regional state administration Oleg Synegubov said.
"Our Armed Forces firmly hold the defensive positions of Kharkiv and the region," he wrote on his Telegram channel.
"That is why the Russian enemy continues to 'fight' with the civilian population due to its powerlessness."
Russian forces are reinforcing around the Donbass region, notably near the town of Izyum, but have not yet launched a full offensive, Pentagon officials said on Monday.
They reported a Russian convoy had been observed heading for Izyum, an hour's drive north of Kramatorsk, saying it appeared to be a mix of personnel-carriers, armoured vehicles and possible artillery.
Ukraine's Defence Ministry said it believed a major assault would happen soon.
"We don't know precisely when, but the preparation is almost over," spokesman Oleksandr Motuzyanyk told a briefing on Monday.
'Logic of war'
Such signs of a build-up in Donbass suggest hopes of an imminent diplomatic solution remain slim.
After a meeting with Russian President Vladimir Putin on Monday, Austrian Chancellor Karl Nehammer said he was "rather pessimistic" of such efforts succeeding as Mr Putin had "massively entered into a logic of war".
Ukraine's allies are trying instead to increase economic and diplomatic pressure on Moscow - but European Union foreign ministers' discussions on a sixth round of sanctions on Monday ended without a consensus.
"Nothing is off the table, including sanctions on oil and gas," Dr Josep Borrell, the EU's top diplomat, told reporters after the meeting. "But today, no decision was taken."
The European police agency Europol, meanwhile, said on Monday it had launched an operation targeting the assets of Russian individuals and companies sanctioned over the war.
In an effort to shore up wider international support for Kyiv, United States President Joe Biden held virtual talks with Indian Prime Minister Narendra Modi just weeks after saying New Delhi had been "shaky" in its response to the invasion.
"There were conversations about how to mitigate the destabilising impacts of Putin's war, including on food supply, where India is in a position to assist," a US official said.
And the UN Security Council - which on Monday held a session on the plight of women and children in Ukraine - will hold another meeting next week on the humanitarian situation there, in a bid to keep pressure on Russia despite its veto power over the body, diplomats said.
'Rape and sexual violence'
At Monday's UNSC meeting, officials called for an investigation into violence against women during the conflict.
"This war must stop. Now," Dr Sima Bahous, director of the UN women's agency, told the meeting.
"We are increasingly hearing of rape and sexual violence. These allegations must be independently investigated to ensure justice and accountability."
More than 4.5 million Ukrainian refugees have now fled their country, the UN refugee agency said - 90 per cent of them women and children.
Russian troops have been accused of widespread atrocities across the country, particularly in areas around Kyiv from which they have now withdrawn, allegations Moscow categorically denies.
Ukraine says more than 1,200 bodies have been found around the capital, with authorities pursuing "500 suspects" including Mr Putin and other top Russian officials.
Seven bodies were found on Monday under the rubble of two multi-storey buildings in the town of Borodyanka, the state emergency service said, bringing the total to 19.
Lithuania's Prime Minister, who was touring the town, said she had "no words" to describe the devastation and accused Russia of war crimes.
"The images of the ruined Ukrainian towns and cities, and the testimonies of the survivors, reveal the real face of Russia," Ms Ingrida Simonyte said.
French investigators have arrived in Ukraine to help probe suspected war crimes, and the European Union has earmarked €2.5 million (S$3.7 million) to the International Criminal Court for future Ukraine cases.
The global consequences of the war were evident on Monday as the World Trade Organisation (WTO) projected world trade growth could almost halve this year.
The WTO said the conflict was a "severe blow" to the world's economy which in the longer term could even spark a disintegration of the global economy into separate blocs.
Russia was also blamed for an escalating global food crisis by the EU's Dr Borrell, because of its bombing of wheat stocks and preventing ships from carrying grain abroad.