President Putin has warned Ukraine's leaders are "calling into question the future of Ukrainian statehood" by resisting his invasion.
It comes as Russian troops broke a ceasefire, according to senior officials, intended to give Ukrainian civilians a chance to evacuate two cities under siege.
The Russian military had said it would observe a ceasefire in Mariupol in the south-east and the eastern town of Volnovakha from 7am UK time on Saturday, expected to last until 2pm UK time.
But Vladimir Putin's forces failed to adhere to the agreement, the Ukrainian presidential office said, causing evacuations to be halted.
On Sunday a second period of ceasefire for Mariupol was announced, from 8am to 7pm UK time with evacuation of the city set to begin from 10am UK time.
President Putin has continued to pin the blame for his war squarely on Ukraine's leadership and slammed their resistance to the invasion.
“If they continue to do what they are doing, they are calling into question the future of Ukrainian statehood,” he said Saturday. “And if this happens, it will be entirely on their conscience.”
Russia's president also hit out at sanctions that have crippled Russia’s economy and sent the value of its currency tumbling.
President Putin said: “These sanctions that are being imposed, they are akin to declaring war,” he said during a televised meeting with flight attendants from Russian airline Aeroflot. “But thank God, we haven’t got there yet.”
The number of people fleeing Ukraine has reached 1.4 million, just 10 days after Russian forces invaded, as an Ukrainian official said the next round of talks between Ukraine and Russia will be held on Monday.
A ceasefire had been agreed in two cities, but the attacks continued on Saturday, as Correspondent Romilly Weeks reports
Kyrylo Tymoshenko, the deputy head of President Volodymyr Zelenskyy’s office, said the city of Mariupol remained under fire.
“The Russian side is not holding to the ceasefire and has continued firing on Mariupol itself and on its surrounding area,” he said.
“Talks with the Russian Federation are ongoing regarding setting up a ceasefire and ensuring a safe humanitarian corridor.”
The Deputy Mayor of Mariupol, Sergei Orlov, told ITV News the city is under constant attack and that he doesn't know how or when they can safely evacuate residents.
He added that they're seeing dead people on the street, but such is the danger from rocket fire that they "cannot even collect them."
'There is no safe place in this city': Mariupol's deputy mayor tells ITV News Mariupol is still under attack
"We saw continued shelling… they continue to destroy this city, they continue to kill people on the street," he said.
"There is no safe place in the city, they continue bombing, using rockets all over the city.
"They [the city's residents] see dead people on the street and we cannot even collect them."
Mariupol has faced a sustained assault by Russian forces, where doctors have made unsuccessful attempts to save the lives of wounded children, pharmacies have run bare and thousands of people faced food and water shortages in freezing weather.
The Ministry of Defence said Russia’s proposed ceasefire was “likely an attempt to deflect international condemnation while resetting its force for renewed offensive activity”.
In an intelligence update on Saturday afternoon, the MoD said: “By accusing Ukraine of breaking the agreement, Russia is likely seeking to shift responsibility for current and future civilian casualties in the city.”
Russia breached the ceasefire deal in Volnovakha as well, Deputy Prime Minister Iryna Vereshchuk told reporters. “We appeal to the Russian side to stop firing,” she said.
The human corridors were highlighted as vital by Mr Zelenskyy on Saturday, insisting it "must work today" to "save women, children and the elderly."
But as Global Security Editor Rohit Kachroo explained from Kyiv before reports of Russia's shelling resuming, there were doubts over the Kremlin's true intentions to begin with.
'There is a great deal of suspicion': Global Security Editor Rohit Kachroo breaks down why many do not trust Russia's promise of civilian evacuations
Speaking from the capital, Kyiv, he said: "This temporary ceasefire, this civilian, humanitarian corridor, which is being started up, there is a great deal of suspicion about that.
"What we’ve seen before in Syria, for example, is ceasefires announced by Russian authorities which have then been used as a front to call everyone who decided to remain as aggressors.
"In Syria it was ‘jihadists.’ So there is some suspicion of what the motives might be behind Russia’s agreement to this ceasefire."
Thousands continue to flee from Ukraine in large numbers into Poland - which is where US Secretary of State Anthony Blinken travelled today - telling some of the refugees he's sorry for their plight, ITV News Correspondent Rebecca Barry reports
Mr Orlov, speaking before the ceasefire was broken, told ITV News there are 50 buses to ferry up to 6,000 people from his city to Zaporizhzhia, 220 kilometres north-west of Mariupol.
The head of Ukraine’s security council, Oleksiy Danilov, had called on Russia to create humanitarian corridors to allow children, women and the elderly to escape the fighting, calling such corridors “question number 1.”
In Moscow, Israeli Prime Minister Naftali Bennett met with Putin at the Kremlin. Israel maintains good relations with both Russia and Ukraine, and Bennett has offered to act as an intermediary in the conflict, but no details of Saturday’s meeting have emerged.
President Volodymyr Zelenskyy reiterated his call for a no-fly zone and told US senators he wants planes and fighter aircrafts, ITV News US Correspondent Emma Murphy reports
It comes as Ukraine's president warned "if Ukraine falls, so will Europe" amid further calls for a no-fly-zone over the country.
He also warned NATO in a virtual address to supporters "all the people who die from this day forward will also die because of you, because of your weakness, because of your lack of unity."
The Ukrainian president has also made a “desperate plea” to US senators on Saturday to send more planes to help the country fight the Russian invasion in a private video call.
War in Ukraine: Special ITV News coverage as Russian invasion enters eleventh day
He opened the call to the 300 members of Congress by telling them this may be the last time they see him alive. He has remained in Kyiv, the capital, which has a vast Russian armoured column threatening from the north.
Mr Zelenskyy told them Ukraine needs to secure its skies, either through a no-fly zone enforced by NATO or through the provision of more warplanes so Ukraine could better defend itself. The president has been pleading for a no-fly zone for days, but NATO has refused, saying it could provoke a widespread war with Russia.
The US Congress is working on a $10 billion package of military and humanitarian aide, and Senate Majority Leader Chuck Schumer told Mr Zelenskyy that lawmakers hope to send it quickly to Ukraine.
How far will Putin go and what can the West do to stop him? Listen to the ITV News 'What You Need To Know' podcast