Russian shelling killed 19 civilians and injured 73 more on Saturday in Donetsk region in eastern Ukraine, while all Russia's units were given the order to resume their offensive from all directions, including the storming of the capital Kyiv, news agencies reported.
"On February 26, as a result of Russian shelling, 19 civilians were killed, 73 people were injured," Interfax quoted Pavel Kirilenko as saying on social media.
Russian forces continued to pound Kyiv and other cities with artillery and cruise missiles in a campaign that has sent hundreds of thousands of Ukrainians fleeing westwards towards the European Union, clogging major highways and railway lines.
Top Russian security official and ex-president Dmitry Medvedev said military operations would be waged relentlessly until President Vladimir Putin's goals were achieved, ratcheting up Moscow's rhetoric.
Putin launched what he called a special military operation on Thursday, ignoring Western warnings and saying the "neo-Nazis and drug addicts" ruling Ukraine threatened Russia's security. The assault threatens to upend Europe's post-Cold War order.
The United States has observed more than 250 launches of Russian missiles, mostly short-range, at Ukrainian targets, the U.S. defense official said.
"We know that (Russian forces) have not made the progress that they wanted to make, particularly in the north. They have been frustrated by what they have seen is a very determined resistance," the official said, without providing evidence.
The RIA news agency quoted Russia's Defense Ministry as saying the Russians had paused their offensive in anticipation of talks between Moscow and Kyiv but the offensive resumed after Ukraine refused to negotiate.
An adviser to Ukraine's President Volodymyr Zelensky denied that Kyiv had refused negotiations but said Russia had attached unacceptable conditions. He also said it was untrue that Russia had paused troop movements on Friday.
"We have withstood and are successfully repelling enemy attacks. The fighting goes on," Zelenskiy said in a video message posted on his social media. "We have the courage to defend our homeland, to defend Europe."
Ukrainians faced lengthy queues for money at cash machines and for fuel at petrol stations, where individual sales are mostly limited to 20 liters. Many shops in the city center were closed and the streets were largely empty on Saturday afternoon.
"I was smart enough to stock up food for a at least a month," said Serhiy, out for a walk before the curfew. "I did not trust the politicians that this would end peacefully."
At least 198 Ukrainians, including three children, have been killed and 1,115 people wounded so far in Russia's invasion, Interfax quoted Ukraine's Health Ministry as saying. It was unclear whether the numbers comprised only civilian casualties.
Ukraine, a democratic nation of 44 million people, won independence from Moscow in 1991 and wants to join NATO and the EU, goals Russia opposes. Putin says Ukraine is an illegitimate state carved out of Russia, a view Ukrainians see as aimed at erasing their distinctive history and identity.
Ukraine said more than 1,000 Russian soldiers had been killed. Russia did not release casualty figures.