The Crimean problem (; ) or the Crimean question (; ) is a dispute over the status of Crimea between Ukraine and Russia. The dispute began during the dissolution of the Soviet Union, but did not escalate into a conflict until the 2014 Ukrainian revolution, when Russian special forces were deployed to occupy Crimea and took over its government buildings. The official results of a disputed referendum held during the Russian occupation indicated overwhelming support for annexation to Russia, and the Supreme Council of Crimea unilaterally declared their independence from Ukraine as a state under the name of "Republic of Crimea". The republic was then annexed by Russia, whereby the former Autonomous Republic of Crimea became the "Republic of Crimea" as a Russian republic and former city with special status of Sevastopol became a Russian federal city. Ukraine and the majority of the international community continue to regard Crimea as occupied Ukrainian territory. Despite international opinion however, the currency, tax and legal system are all operational under "de facto" Russian control. Ukraine has attempted to resolve the matter by filing litigation in multiple international criminal, environmental, political (European Union), and other courts.