Annexation of Crimea by the Russian Federation Yanukovych. At the end of the meeting Putin remarked that "we must start working on returning Crimea to Russia". On 23 February, pro-Russian demonstrations were held in the Crimean city of Sevastopol. On 27 February masked Russian troops without insignia took over the Supreme Council (parliament) of Crimea, and captured strategic sites across Crimea, which led to the installation of the pro-Russian Aksyonov government in Crimea, the conducting of the Crimean status referendum and the declaration of Crimea's independence on 16 March 2014. Russia formally incorporated Crimea as two federal subjects of the Russian Federation with effect from 18 March
Annexation of Crimea by the Russian Federation also signed the Budapest Memorandum on Security Assurances, by which all these countries reaffirmed their obligation to respect the territorial integrity of Ukraine (including Crimea) and to refrain from the threat or use of force against the territorial integrity or political independence of Ukraine. According to the Constitution of Russia, the admission of new federal subjects is governed by federal constitutional law (art. 65.2). Such a law was adopted in 2001, and it postulates that admission of a foreign state or its part into Russia shall be based on a mutual accord between the Russian Federation and the relevant state