Russia and Ukraine started their beef in the year 2014 over a boundary possession known as the Crimean Peninsula.
The fresh attack leading to an invasion started because Ukraine wants to join the North Atlantic Treaty Organization (NATO) which was formed in the year 1949 during the cold war era to dissuade the Soviet Union (which is now known as Russia) assault and geopolitical impact.
Due to the fight between the two countries over the control of the Crimean Peninsula which is a territory between them, Russia doesn’t want Ukraine to join Nato which is already consisting of 30 members nation.
In addition, the Russian government has earlier warned Ukraine about restricting other nation hostilities in the eastern Hemisphere which is toward Russia which they are yet to carry out which made president Putin declare war on mainly the eastern part of Ukraine which is the closest to the border of Russia.
