Most western nations have condemned Russia's invasion of Ukraine.
Western leaders on Thursday condemned the Russian invasion of Ukraine, vowing to escalate sanctions against Moscow while the head of the United Nations demanded the conflict end immediately. India called for an immediate desecration while China said it "understands" Russia's concerns.
India
India has said hostility between Russia and Ukraine if not checked would spiral into a major crisis that can severely destabilize the region.
"The situation is in danger of spiralling into a major crisis. We express our deep concern over the developments, which if not handled carefully, may well undermine the peace and security of the region," India's Permanent Representative to the United Nations TS Tirumurti said.
"We call for immediate de-escalation and refraining from any further action that could contribute to a worsening of the situation. We call on all parties to exert greater efforts to bridge divergent interests," Mr Tirumurti said, adding the legitimate security interests of all parties should be taken into account.
United States
"The prayers of the entire world are with the people of Ukraine tonight as they suffer an unprovoked and unjustified attack by Russian military forces," US President Joe Biden said shortly after the operation began.
He warned, "Russia alone is responsible for the death and destruction this attack will bring."
"The world will hold Russia accountable," he declared.
Ukraine
Ukrainian President Volodymyr Zelensky compared Russia's invasion of his country to Nazi Germany's military campaigns during World War II.
"Russia has attacked Ukraine in a cowardly and suicidal way like Nazi Germany did during World War II," Zelensky said in an online briefing.
China
Chinese Foreign Minister Wang Yi told his Russian counterpart, Sergei Lavrov, in a phone call that China understands "Russia's reasonable concerns on security issues", China's foreign ministry said.
The foreign ministry repeatedly declined to call the attack an "invasion" at a press briefing on Thursday.
United Nations
UN chief Antonio Guterres made a direct and personal plea to Russian President Vladimir Putin after an emergency Security Council session, urging him to stop the attack "in the name of humanity."
"Do not allow to start in Europe what could be the worst war since the beginning of the century," he said.
"The conflict must stop now," added the UN chief, who said it was the "saddest day" of his tenure.
NATO
NATO head Jens Stoltenberg said Russia had "chosen the path of aggression against a sovereign and independent country."
The attack "puts at risk countless civilian lives," Stoltenberg said in a statement, describing it as a "grave breach of international law, and a serious threat to Euro-Atlantic security."
NATO ambassadors were to hold an emergency meeting to discuss the attack.
United Kingdom
"I am appalled by the horrific events in Ukraine and I have spoken to President Zelensky to discuss next steps," British Prime Minister Boris Johnson tweeted.
In an address to the nation, Johnson later called Putin a "dictator" facing "massive" sanctions for his "attack on democracy and freedom in east Europe and around the world."
European Union
"In these dark hours, our thoughts are with Ukraine and the innocent women, men and children as they face this unprovoked attack and fear for their lives," European Union chiefs Ursula von der Leyen and Charles Michel said on Twitter.
"We will hold the Kremlin accountable," they added.
Foreign policy chief Josep Borrell said Russia faced "unprecedented isolation" and would face the "harshest sanctions" the EU has ever imposed.
"This is not a question of blocs. This is not a question of diplomatic power games. It's a matter of life and death," he said.
Germany
German Chancellor Olaf Scholz lashed out at an "unscrupulous act" and spoke to Zelensky to express his country's "full solidarity."
Putin is "endangering the lives of countless innocent people in Ukraine... (and) jeopardising peace in our continent," Scholz said.
France
French President Emmanuel Macron said Russia's "act of war" was a "turning point in the history of Europe" with "deep and lasting consequences for our lives" in an address to the nation.
He said the G7, NATO and the European Union would be "without weakness" when they meet to agree on sanctions later on Thursday after Moscow inflicted "the most significant damage on peace and stability in Europe for decades."
Canada
Canadian Prime Minister Justin Trudeau condemned Russia's "egregious" and "unprovoked" attack on Ukraine as "a clear further violation of Ukraine's sovereignty and territorial integrity" and Russia's obligations under international law.
"These reckless and dangerous acts will not go unpunished," he said in a statement.
Japan
"The latest Russian invasion shakes the foundation of the international order, which does not permit unilateral attempts to change the status quo," Japanese Prime Minister Fumio Kishida said after a meeting of his national security council.
Italy
Italian Prime Minister Mario Draghi called Russia's invasion "unjustified and unjustifiable."
"Italy is close to the Ukrainian people and institutions in this dramatic moment," Draghi said in a statement.
Turkey
Turkey, a NATO member with friendly ties with Ukraine and Russia, said the invasion was "unjust and unlawful" in a foreign ministry statement.
President Recep Tayyip Erdogan denounced Moscow's move as a "heavy blow" to regional peace and stability.
South Africa
South Africa said it "calls on Russia to immediately withdraw its forces from Ukraine." It said the country was "dismayed" at the turn of events but stood behind hopes for "diplomatic efforts to find a solution to the concerns... expressed by Russia."