US President Joe Biden on Thursday called his Russian counterpart Vladimir Putin's announcement of a military operation in Ukraine as "an unprovoked and unjustified attack" and that the "world will hold Russia accountable" for the subsequent developments.
In a statement issued by the White House, Biden said that "Putin has chosen a premeditated war that will bring a catastrophic loss of life and human suffering".
"Russia alone is responsible for the death and destruction this attack will bring, and the US and its Allies and partners will respond in a united and decisive way," he said.
Biden said that he will be monitoring the situation in Ukraine and will will meet his G7 counterparts on Friday morning after which further actions will be taken.
Just three days after declaring the rebel regions of Donetsk and Luhansk in eastern Ukraine as independent states, Putin on Thursday morning announced a military operation in the Donbas region, asking Ukrainian troops to lay down their weapons and return home.
Unfazed by the numerous economic sanctions imposed by the international community against Moscow, Putin said Russia did not plan to occupy Ukraine, but warned that Moscow's response would be "instant" if anyone tries to take on Russia.
Ukrainian Foreign Minister Dymtro Kuleba said in a tweet that "Putin has just launched a full-scale invasion of Ukraine. Peaceful Ukrainian cities are under strikes. This is a war of aggression".
"Ukraine will defend itself and will win. The world can and must stop Putin. The time to act is now."