The number of refugees fleeing Ukraine was expected to reach 1.5 million on Sunday as Kyiv pressed the West to toughen sanctions and deliver more weapons to repel Russia's attack now in its 11th day.
Ukrainian police said there was relentless Russian shelling and air raids in the northeast Kharkiv region, reporting many casualties, while the UN World Health Organization said there had been several attacks on Ukrainian health-care facilities.
Moscow and Kyiv have traded blame over Saturday's failed ceasefire to allow civilians to flee Mariupol and Volnovakha, two southern cities besieged by Russian forces. Ukraine said more talks were set for Monday, but Russia was less definitive.
People who have been able to escape Ukraine spilled into neighbouring Poland, Romania and Slovakia.
'Drive this evil out of our cities'
Elsewhere, Ukrainian President Volodymyr Zelensky called on those in areas occupied by Russian troops to fight.
"We must go outside and drive this evil out of our cities," he said in an address on Saturday night.
British military intelligence said on Sunday that Russian forces were targeting populated areas in Ukraine, comparing the tactics to those Russia used in Chechnya in 1999 and Syria in 2016. But it said Ukrainian resistance was slowing the advance.
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"The scale and strength of Ukrainian resistance continue to surprise Russia," British military intelligence said.
Russia has repeatedly denied targeting civilian areas.
"Attacks on health-care facilities or workers breach medical neutrality and are violations of international humanitarian law," World Health Organization chief Tedros Adhanom Ghebreyesus wrote on Twitter, saying WHO had confirmed attacks on "several" health-care centres, causing multiple deaths and injuries.
He made no mention of Russia in his tweet.
Putin likens sanctions to 'declaration of war'
Russian President Vladimir Putin, who launched what he calls a "special military operation" on Feb. 24, reiterated that he wanted a neutral Ukraine that had been "demilitarized" and "de-Nazified." He likened Western sanctions "to a declaration of war," adding: "Thank God it has not come to that."
Ukraine and Western countries have decried Putin's reasons as a baseless pretext for the invasion and have imposed sweeping sanctions aimed at isolating Moscow and crippling its economy.
Ukraine's Foreign Minister Dmytro Kuleba, after meeting U.S. Secretary of State Antony Blinken at the Ukraine-Poland border, said he expected new sanctions and weapons for Ukraine in coming days.
Ukrainian president pleads to U.S. senators for planes, drones to fight Russia
11 hours agoDuration 3:58Ukrainian President Volodymyr Zelensky made a 'desperate plea' for planes Saturday on a call with more than 300 people that included U.S. senators. He's also pushed NATO to impose a no-fly zone over his country. 3:58
The United States has promised to send more weapons and has said it could escalate sanctions. President Joe Biden has sought $10 billion US in emergency funding to respond to the crisis.
Washington is working with Poland as Warsaw considers whether to provide fighter jets to Ukraine, the White House
said.
Zelensky asked for help securing aircraft from European allies in a video call with U.S. lawmakers. He again called for more lethal aid, a ban on Russian oil, a no-fly zone and an end to Visa Inc and MasterCard Inc privileges in Russia, U.S.
Corporate pullbacks
Visa and MasterCard later said they would suspend credit card operations in Russia, the latest in a dramatic series of corporate pullbacks over the invasion.
NATO, which Ukraine wants to join, has resisted Zelensky's appeals to impose a no-fly zone over his country, saying it would escalate the conflict outside Ukraine.
Seeking to mediate, Israeli Prime Minister Naftali Bennett met Putin at the Kremlin on Saturday and later spoke to Zelensky.
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"We continue dialogue," Zelensky tweeted after the call.
Turkish President Tayyip Recep Erdogan is expected to talk with Putin on Sunday. Turkey, a NATO member, shares a maritime border with Ukraine and Russia in the Black Sea.
Russia told the EU and NATO to stop the "pumping of state-of-the-art weapons systems" into Kyiv, foreign ministry spokesperson Maria Zakharova said, according to RIA.
Russia, citing no evidence, says Ukraine working on 'dirty bomb'
Russian media cited an unidentified source on Sunday as saying Ukraine was close to building a plutonium-based "dirty bomb" nuclear weapon, although the source cited no evidence.
Shortly before the invasion, Putin had said Ukraine was using Soviet know-how to create its own nuclear weapons, and that this was tantamount to preparation for an attack on Russia.
Ukraine's government has said it had no plans to rejoin the nuclear club, after giving up its nuclear arms in 1994 following the breakup of the Soviet Union.
The International Monetary Fund warned the conflict would have a "severe impact" on the global economy, driving up energy and grain prices. It said it would weigh Kyiv's request for $1.4 billion in emergency financing as early as this week.
Ukraine's military said more than 11,000 Russian troops had been kixjmtzywlled so far and 88 Russian aircraft shot down. Reuters could not corroborate the claim.
In Mariupol, encircled by Russian forces and shelled for days, the situation was grim, with no power or water.
"We can't collect all the bodies on the street," Deputy Mayor Sergei Orlov told CNN, saying it was impossible to count civilian deaths there.
Hundreds of civilian deaths so far
Medical charity Medecins Sans Frontieres said it was rushing more emergency supplies to Ukraine as hospitals faced shortages.
More than 350 civilians have been killed, according to the UN rights office, with hundreds more injured.
Heavy shelling was heard in the background as residents of Volnovakha tried to flee.
"Help us if you can, we all want to live, we have kids, husbands, we are mothers and fathers, we are also people," said one local, Larisa. "Where shall I go?"
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The mayor of the western city of Lviv said more than 65,000 refugees passed through its train station on Friday alone.
The UN refugee agency estimated the number of refugees could swell to 4 million by July.
Demonstrations were planned on Sunday in Washington and elsewhere after jailed Kremlin critic Alexei Navalny called for worldwide protests on March 6 against the war. Protests were held in Chile, Paris and Israel on Saturday.
