US President Joe Biden paid an unannounced visit to Kiev on Monday and pledged a $500 million military aid package, almost a year after the Russo-Ukrainian war began. The United States, by far the largest supplier of military aid to Ukraine since Russia's military operation began last February, also announced an additional $500 aid package that includes more military equipment and weapons such as Javelin anti-tank missiles becomes. During the visit, Biden pledged that Washington will stand by Ukraine for as long as it takes.

Russia has repeatedly announced that supporting and supplying arms to Ukraine from the US and its allies will only prolong the conflict. "Despite all the disagreements we have in our Congress on some issues, there is a significant consensus to support Ukraine," Biden said. Zelenskyy said Biden's visit was "an extremely important sign of support for all Ukrainians". On Saturday, at the annual Munich Security Conference, US Vice President Kamala Harris accused Russia of committing crimes against humanity during its nearly year-long "military operation" against Ukraine and vowed it will be held accountable for its actions.

Russia's Ambassador to the United States Anatoly Antonov said in a statement Sunday Washington plans to demonize Moscow and fuel the crisis in Ukraine with allegations of crimes against humanity. "We view such allegations as an unprecedented attempt to demonize Russia as part of the hybrid war unleashed against us," he said. Bloomberg News reported on Sunday that the new sanctions will affect Russia's defense and energy sectors, financial institutions and a range of individuals. Moscow says the operation aims to stop Kiev's persecution of the pro-Russian population in eastern Ukraine and also serves to "denazify" the ex-Soviet republic.