Inside Russia- Ukraine.
After the end of world war II which concluded with the liberation of German-occupied territories, the decline of European colonial empires the world was shaping towards a new era and the rise of two major blocs in the world known as the western bloc and eastern bloc which was led by US and USSR respectively were the emerging powers. This division further led to the cold war between (1947–1989), it is called the cold war as there was no direct confrontation between the two organizations, instead, the war was fought based on an ideological basis and in proxy wars.
This grouping of the US and USSR countries led to the formation of NATO( North Atlantic treaty organization) on April 4, 1949, it had 12 countries in the beginning now it has expanded its territories to 30 countries, North Macedonia being the latest to join NATO. NATO is the first peacetime military alliance, its major goal was to protect the West from the rise of the USSR, to rebuild their economy and prevent communist expansion.
-NATO( April 4, 1949- Current )
In a similar way, another collective defence pact was signed as a counterweight to the NATO in Warsaw, Poland known as the Warsaw Pact, it consisted of 7 socialist republics(Eastern Bloc countries) also known as the BIG SEVEN, this pact does not exist, anyone, as it ended with the solidarity movement in Poland in 1989, east Germany also withdrew from the pact following the reunification of Germany in 1990. On 1991 November 4 the pact was declared null and void by the defence minister of the six remaining countries. On December 25, 1991, the USSR also came to an end.
USSR (December 30, 1922- December 25, 1991)
-Warsaw Pact( 1955–1991)
After the above details, we can be clear that the USA and USSR always had some tensions with each other.
Ukraine is in many ways torn between the East and the west, in the west the EU, NATO and in the east is Russia has heavily influenced the country for decades. The population of Ukraine is split between two groups, one which wants Ukraine to be the Part of the Western world and the other population who vote Ukraine to be the part of Russia. In 2010, Viktor Yanukovych whose majority of the voters were in support of Russia won the presidential election but, later in 2013 the people wanted Anukovych to step down as the corruption and human rights violation increased and expressed their way for European integration, in the meantime this conflict was used by the people who lived in the eastern part of the country, they overthrew the Crimean president and sought help with Putin. Crimea is one of the most disputed regions which has changed its status between Russia and Ukraine several times. We can see the influence of Russia in Crimea by looking at the language spoken in the figure below. The referendum was held in Crimea in 2014, which the majority of the people voted in favour of Crimea to join the Russian Federation (97%). Vladimir Putin then taking the advantage of the situation disarmed the Ukrainian army and took the Crimean Peninsula on 18th March 2014, this action was seen as a violation of international law by the western world.
The other regions of eastern Ukraine named Luhansk and Donetsk, Donbas in common is full of separatist who feel that they’ve been ignored by Kyiv and wants to join Russia. Taking this advantage Putin declared Luhansk and Donetsk as independent states and started the war on 24th February 2022.