In February and March 2014, Russia invaded the Crimean Peninsula, part of Ukraine, and then annexed it. This took place in the relative power vacuum immediately following the Revolution of Dignity. It marked the beginning of the Russo-Ukrainian war.
The events in Kyiv that ousted Ukrainian president Viktor Yanukovych on 22 February 2014 sparked both pro-Russian and anti-separatism demonstrations in Crimea. At the same time, Russian president Vladimir Putin told his security chiefs to begin work on "returning Crimea to Russia". On 27 February, Russian special forces without insignia seized strategic sites across Crimea. Russia at first denied involvement, but Putin later admitted that they were Russian troops. As the armed men occupied Crimea's parliament, it dismissed the Crimean government, installed the pro-Russian Aksyonov government, and announced a referendum on Crimea's status. The referendum was held under Russian occupation and, according to the Russian-installed authorities, the result was overwhelmingly in favor of joining Russia. The next day, 17 March 2014, Crimea's authorities declared independence and requested to join Russia. Russia formally incorporated Crimea on 18 March 2014 as the Republic of Crimea and federal city of Sevastopol. Following the annexation, Russia militarized the peninsula and warned against any outside intervention.
