President Volodymyr Zelenskyy and western leaders struck a defiant note on Friday as Ukraine marked the anniversary of Russia's invasion.
Mr Zelenskyy saluted his people for a “year of invincibility” in which Ukraine “inspired the world” by resisting Moscow's troops.
“We endured. We were not defeated. And we will do everything to gain victory this year,” he said.
Nato allies renewed their vows of solidarity as a war that Russia hoped to win in days enters its second year with no end in sight.
In a symbolic vote, the UN General Assembly passed a resolution demanding a Russian withdrawal, supported by 141 countries and opposed by seven.
Landmarks including the Eiffel Tower in Paris were lit up in Ukraine's blue and yellow, while UK Prime Minister Rishi Sunak held led a minute's silence in Downing Street.
In Kyiv, Mr Zelenskyy awarded medals to families of the fallen and handed battle flags to Ukrainian assault brigades.
Visiting the capital, Poland's Prime Minister Mateusz Morawiecki said his country had already delivered four German-made Leopard tanks to Ukraine.
Support for Ukraine on the anniversary of the war - in pictures
Members of Nato used a joint statement to pay tribute to Ukrainians for their “heroic defence of their nation, their land, and our shared values”.
“Russia’s efforts to break the resolve of the brave people of Ukraine are failing,” they said. “One year on, Ukrainians are fighting valiantly for freedom and independence. We stand with them.”
The UK announced new export bans on “every item Russia has been found using on the battlefield”.
Leaders of the G7 countries — the US, Canada, Britain, France, Germany, Italy and Japan — were to hold virtual talks later on Friday.
Mr Sunak said he would urge allies to give Ukraine a “decisive advantage on the battlefield” to force Russia into retreat. German Chancellor Olaf Scholz said western aid would hasten the day when Russian President Vladimir Putin “realises he will not achieve his imperialist goals”.
Britain's King Charles paid tribute to the “remarkable courage and resilience” of Ukrainians in the face of what he called an “unprovoked full-scale attack on their nation”.
In Russia, former president Dmitry Medvedev — an ally of Mr Putin — declared on Friday that “victory will be achieved”.
In his latest warning, Mr Medvedev said Russia's aim was to “push back the borders that threaten our country as far as possible, even if they are the borders of Poland”.
China unveiled what it called a 12-point peace plan, which urged a ceasefire and an end to Russia's nuclear threats, while also opposing sanctions and suggesting both sides had valid concerns.
Western leaders reacted cautiously. European Commission president Ursula von der Leyen said China had already “taken sides” with Russia, while German President Frank-Walter Steinmeier said it was “questionable whether China wants to play a constructive role”.
The UN's nuclear watchdog meanwhile said Ukraine had been fortunate to avoid a nuclear disaster after shelling near the Zaporizhzhia plant.
Mr Putin announced the invasion at dawn on February 24, 2022, claiming Russia was under threat from a western-backed Ukraine.
He said Russia's “special military operation” was meant to demilitarise Ukraine and protect the Russian-speaking minority in the east of the country.
The West rejected these as baseless excuses for a war of aggression to seize Ukrainian territory and force Ukraine back into Moscow's orbit.
The US and its allies responded with massive sanctions on Russia and an increasing flow of weapons to Ukraine, helping it stall the invasion.
They are now watching China's next move amid speculation that it could provide arms to Russia.
Fear of Russian attack prompted Sweden and Finland to seek Nato membership, a process delayed by Turkish objections.
Nato Secretary General Jens Stoltenberg said on Friday that he saw progress on that front with Turkey, Sweden and Finland to hold talks in Brussels next month.
“Both Finland and Sweden have lived up to the commitments they signed up to at the Nato summit last year so I think the time has come to ratify both now,” he said.
Millions of Ukrainians have fled their country, while those who stayed behind have seen homes destroyed and power cuts caused by Russian bombardment. Around the world, the war has led to a surge in food and energy prices.
Human rights inspectors at the Organisation for Security and Co-operation in Europe said the war was having a “devastating effect” on civilians.
“The consequences of the conflict that started one year ago will be felt for generations to come by the people of Ukraine,” said Matteo Mecacci, the OSCE's human rights director.