Russia on Saturday ordered its troops to advance in Ukraine "from all directions" as the Ukrainian capital Kyiv imposed a blanket curfew and officials reported 198 civilian deaths.
Kyiv residents took shelter to the sound of explosions as Ukraine's army said it had held back an assault on the capital but was fighting Russian "sabotage groups" which had infiltrated the city.
Moscow said it had fired cruise missiles at military targets and would "develop the offensive from all directions" after accusing Ukraine of having "rejected" talks.
But, on day three of Russia's invasion, a defiant Ukrainian President Volodymyr Zelensky vowed his country would never give in to the Kremlin.
Zelensky spoke in a video message, wearing olive green military-style clothing and looking tired but determined.
"I am here. We will not lay down any weapons. We will defend our state, because our weapons are our truth," the 44-year-old said.
"Our truth is that this is our land, our country, our children and we will protect all of this."
He later said Ukraine had "derailed" the Russian plan of overthrowing him and urged Russians to pressure Putin into stopping the conflict.
Ignoring warnings from the West, Russian President Vladimir Putin unleashed a full-scale invasion that the UN refugee agency said has forced almost 116,000 people to flee to neighbouring countries.
Tens of thousands more are estimated to be displaced within Ukraine, with many on the move to western areas of the country less affected by the fighting.
Ukrainian Health Minister Viktor Lyashko said 198 civilians, including three children, had been killed in the conflict and 1,115 wounded.
In Kyiv, residents took shelter in the subway system and in cellars and basements.
"We thought something like this might happen, but we were hoping until the end that it wouldn't," Irina Butyak told AFP in one shelter.
"We were hoping that common sense and common decency would prevail. Well, it didn't," the 38-year-old teacher said.
Thousands of refugees made their way to the Polish border city of Przemysl by train.
"We don't want to be running from country to country and asking for support, but support is really needed this time," one refugee, who only gave her first name, Anna, told AFP.
In Paris, French President Emmanuel Macron warned that the world must brace for a long war.
"This crisis will last, this war will last and all the crises that come with it will have lasting consequences," Macron said.
"We must be prepared".
After speaking to Macron, Zelensky tweeted to thank "partners" for sending weapons and equipment.
Several NATO members have sent weapons and ammunition to Ukraine in recent weeks, including Britain, the United States and ex-communist countries in eastern Europe.
In the latest contribution from Washington, Secretary of State Antony Blinken announced $350 million (310 million euros) in additional military equipment.
NATO has said it is deploying its rapid response force of 40,000 troops to eastern Europe for the first time, but the Western military alliance has made clear it will not send any troops to Ukraine.
In the early hours of Saturday, AFP reporters in Kyiv heard occasional blasts of what soldiers said were artillery and Grad missiles being fired in an area northwest of the city centre.
There were also loud explosions in the centre.
Emergency services said a high-rise apartment block was hit by shelling overnight, posting a picture that showed a hole covering at least five floors blasted into the side of the building.
Kyiv's mayor, Vitali Klitschko, said the building had been hit by a missile.
"The enemy is trying to break into the city, in particular from Gostomel, Zhytomyr, where the aggressors are neutralised," Klitschko said, referring to two settlements to the northwest and west of the city.
"Now in Kyiv there are, unfortunately, sabotage groups, there were several clashes," he said.
Hours later, AFP saw a destroyed Ukrainian military truck in the city centre and a civilian volunteer digging a trench for soldiers.
Ukrainian army tanks were also seen manoeuvring all over the centre but the streets were mostly empty and the centre silent except for the sound of air raid sirens and birdsong.
The city said it was toughening a curfew in place and anyone on the streets after 5:00 pm (1500 GMT) would be considered "members of the enemy's sabotage and reconnaissance groups".
The curfew will last until 8:00 am on Monday.
Elsewhere in Ukraine, AFP saw traces of an airstrike on a military base near the village of Rozsishki in central Ukraine, including two destroyed trucks.
At the entrance to several villages and towns on the way to Lviv, men in civilian clothes could be seen manning improvised concrete barriers.
When he announced the beginning of the assault Thursday, Putin said it was to defend Russia-backed separatists in eastern Ukraine.
The rebels have been fighting Ukrainian government forces for eight years in a conflict in which more than 14,000 people have been killed.
Putin called the current conflict a "special military operation" and Russia's communications regulator on Saturday told independent media to remove reports describing it as an "assault, invasion, or declaration of war".
In a statement, the regulator accused the media outlets of spreading "untrue information" about the shelling of Ukrainian cities by the Russian army and civilian deaths.
Russia has brushed off international condemnation and increasingly stringent sanctions adopted by the United States, Canada, Britain and the European Union, including against Putin himself and Foreign Minister Sergei Lavrov.
Moscow said sanctioning the pair was "a demonstration of the complete impotence of the foreign policy" of the West.
Zelensky has called on Western allies to go further by expelling Moscow from the SWIFT banking transfer system -- a move that would cripple Russia's trade with most of the world.
But a number of EU countries, including Germany, Hungary and Italy, have been reluctant over fears Russia could cut off gas supplies.
Polish Prime Minister Mateusz Morawiecki slammed countries such as Germany, which Warsaw has long criticised for its economic ties to Russia.
"There is no time today for the kind of unyielding egoism that we see in certain Western countries, including here in Germany unfortunately," Morawiecki said in Berlin ahead of a meeting with German Chancellor Olaf Scholz.
"That is why I came here... to shake the conscience of Germany. So that they finally decide on sanctions that are actually crushing," he told Polish reporters.
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