Russian and Ukrainian officials met on the Belarusian border to discuss a ceasefire on Monday while invading Russian forces encountered determined resistance from Ukrainian troops and civilians on a fifth day of conflict.
Russia faced deepening isolation and economic turmoil as Western nations, united in condemnation of its assault, hit it with an array of sanctions that created ripple effects around the world. Global shares slid and oil prices jumped.
But Russian leader Vladimir Putin did not appear ready yet to think again about the invasion he unleashed on Russia's western neighbour last Thursday, dismissing the West as an "Empire of Lies" and putting his nuclear-armed units on high alert, reports Reuters.
In the northeastern city of Kharkiv, Ukraine's second largest, Russian forces fired on residential areas on Monday, killing dozens and wounding hundreds of people, the Ukraine military said.
Video posted by the military showed thick plumes of smoke rising from apartment blocks and flashes of flames, apparently from missiles impacting. Reuters could not independently confirm the accounts.
Fighting took place throughout the night around the port city of Mariupol, the head of the Donetsk regional administration, Pavlo Kyrylenko, said. He did not say whether Russian forces had gained or lost ground.
Russian forces seized two small cities in southeastern Ukraine and the area around a nuclear power plant, the Interfax news agency said.
But they ran into stiff resistance elsewhere as the biggest assault on a European state since World War Two failed to make as much ground in its early days as some had expected.
The capital Kyiv was still held by the Ukrainian government, with President Volodymyr Zelenskiy, dressed in military gear, encouraging his people with a series of defiant messages.
Blasts were heard in the city before dawn and Ukrainians set up checkpoints and blocked streets with piles of sandbags and tyres as they waited to take on Russian soldiers.
In the basement of Ohmadyt Children's Hospital in Kyiv, mothers and babies huddled on makeshift beds and blankets laid out on either side of the concrete aisle.
On the streets, signboards normally used for traffic alerts showed the message: "Putin lost the war. The whole world is with Ukraine".
TALKS
The talks between the two sides were aimed at securing an immediate ceasefire and the withdrawal of Russian forces, the Ukrainian president's office said. The Kremlin has declined to comment on Moscow's goals.
They are being held on the border with strong Russian ally Belarus - a launch pad for the invading Russian troops.
The Russian delegates wore formal suits while the Ukrainians had on plain dark clothes and, in one case, a baseball cap.
Hours after they started, there was no word on any developments but Ukrainian presidential adviser Mykhailo Podolyak said they were continuing.
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.
The Western-led response has been emphatic, with sanctions that effectively cut off Moscow's major financial institutions from Western markets. Russia's rouble currency plunged 32% against the dollar on Monday before recouping about half of its losses. Countries also stepped up weapons supplies to Ukraine.
In Brussels, the European Union's foreign policy chief Josep Borrell said the EU sanctions would have a cost for Europe "but we have to be ready to pay the price, or we will have to pay a much higher price in the future".
The EU would provide intelligence to Ukraine about Russian troop movements and EU countries were determined to increase their military support to Kyiv, Borrell said.
France said President Emmanuel Macron spoke to Putin on Monday and urged an immediate ceasefire and an end to attacks on civilians and infrastructure.
BATTLE FOR CITIES
The Ukrainian military said Russian forces were focusing on Chernihiv city, northeast of Kyiv, and parts of Donetsk region in the east. Separatists raised a Russian flag on a local administration building in one shattered village on Sunday, Reuters footage showed.
Russia said its forces had taken over the towns of Berdyansk and Enerhodar in Ukraine's southeastern Zaporizhzhya region as well as the area around the Zaporizhzhya nuclear power plant, Interfax reported. The plant's operations continued normally, it said.
Ukraine denied the nuclear plant had fallen into Russian hands, Interfax said.
UN human rights chief Michelle Bachelet said at least 102 civilians in Ukraine have been killed since Thursday, with a further 304 wounded, but the real figure is feared to be "considerably higher".
More than half a million people have fled to neighbouring countries, according to the United Nations refugee agency.
Partners in the US-led NATO (North Atlantic Treaty Organization) defence alliance were providing Ukraine with air-defence missiles and anti-tank weapons, NATO chief Jens Stoltenberg said.
The Kremlin accused the European Union of hostile behaviour, saying weapons supplies to Ukraine were destabilising and proved that Russia was right in its efforts to demilitarise its neighbour.
The Kremlin declined to comment on whether there was a risk of confrontation between Russia and NATO. Russia has demanded that NATO never admit Ukraine.
Over the weekend, Western nations announced sanctions including blocking some Russian banks from the SWIFT international payments system.
In an emergency move, Russia's central bank raised its key interest rate to 20 per cent from 9.5 per cent as the rouble slid. Authorities told export-focused companies to be ready to sell foreign currency.
It also ordered brokers to block attempt by foreigners to sell Russian securities.
Corporate giants also took action in response to the sanctions, with British oil major BP, the biggest foreign investor in Russia, saying it would abandon its stake in state oil company Rosneft at a cost of up to $25 billion.
PROTESTS
Protests have been held around the world against the invasion, including in Russia, where almost 6,000 people have been detained at anti-war demonstrations since Thursday, the OVD-Info protest monitor said.
The UN Human Rights Council agreed on Monday to hold a debate on Thursday on the invasion after Kyiv's ambassador told the Geneva forum that some of Moscow's military actions "may amount to war crimes".
Zelenskiy on Monday asked the European Union to allow Ukraine to gain membership immediately.
The EU shut all Russian planes out of its airspace, as did Canada, forcing Russian airline Aeroflot to cancel all flights to European destinations until further notice.
Ukraine's Foreign Minister Dmytro Kuleba urged the Russian people to demand Putin stop the war.
"Look what Vladimir Putin turned your country, your great country, into. He declared an invasive war against Ukraine, he sent your sons, husbands here to kill Ukrainians, capture our lands, destroy our cities. Ukrainians did not want this war, but they will fight for their land," he said in a video.