The Russo-Ukrainian War is an ongoing interstate conflict between the Russian Federation and Ukraine. The war began in February 2014 and escalated significantly with Russia's full-scale invasion on February 24, 2022.
The conflict originated after Ukraine gained independence from the Soviet Union in 1991 and began seeking closer ties with Western nations. The immediate catalyst was the ousting of pro-Russian President Viktor Yanukovych in 2014. Russia responded by annexing the Ukrainian peninsula of Crimea in February 2014 and supporting armed separatists in the eastern Donbas region. A key underlying reason for the conflict, from Russia's perspective, is the perceived threat of North Atlantic Treaty Organization (NATO) expansion along its borders.
The mechanism for de-escalation that failed was the Minsk Agreements, a series of international agreements signed in September 2014 (Minsk-I) and February 2015 (Minsk-II). These agreements sought a ceasefire, monitoring by the OSCE, and decentralization of power in the Donetsk and Luhansk oblasts. However, the agreements failed to end hostilities, and Russia declared them defunct just before the 2022 invasion.
The war connects directly to the concept of NATO expansion and the broader geopolitical struggle over Ukraine's post-Soviet alignment. The conflict changed drastically on February 24, 2022, when the full-scale invasion replaced the limited war in Donbas. Since then, Russia has also claimed the annexation of four more Ukrainian regions: Donetsk, Kherson, Luhansk, and Zaporizhzhia.