Beginning on 26 February, pro-Russian forces, subsequently confirmed to be Russian troops by Vladimir Putin, began to gradually take control of the Crimean Peninsula.
During this time, the question of joining the Russian Federation was put to a referendum, which had an official turnout of 83 per cent and resulted in a 96% affirmative vote but has been condemned by the EU, the United States, Ukrainian and Crimean Tatar officials as contrary to Ukraine's constitution and to international law.
On 17 March, the Crimean Parliament declared independence from Ukraine and asked to join the Russian Federation.
On 18 March, Russia and Crimea signed a treaty of accession of the Republic of Crimea and Sevastopol into the Russian Federation.
On 21 March, the accession treaty was ratified and the establishment of two new constituent entities in the Russian Federation was marked by a 30 gun salute under an executive order of the Russian President.
The U.N. General Assembly passed a non-binding resolution that declared that the referendum was invalid, and the incorporation of Crimea into Russia as illegal.

By 1 April, around 3,000 people had fled Crimea after its annexation.
80% of those who fled were Crimean Tatars.
Teams from the Organization for Security and Co-operation in Europe in Ivano-Frankivsk Oblast and Chernivtsi Oblast have assisted internally displaced persons who have resettled in western Ukraine from Crimea.
Numbers of refugees, primarily Crimean Tatars, continued to rise, and by 20 May the Office of the United Nations High Commissioner for Refugees (UNHCR) said that about 10,000 people had been displaced.
Beginning on 26 February, pro-Russian forces, subsequently confirmed to be Russian troops by Vladimir Putin, began to gradually take control of the Crimean Peninsula. During this time, the question of joining the Russian Federation was put to a referendum, which had an official turnout of 83 per cent and resulted in a 96% affirmative vote but has been condemned by the EU, the United States, Ukrainian and Crimean Tatar officials as contrary to Ukraine's constitution and to international law. On 17 March, the Crimean Parliament declared independence from Ukraine and asked to join the Russian Federation. On 18 March, Russia and Crimea signed a treaty of accession of the Republic of Crimea and Sevastopol into the Russian Federation. On 21 March, the accession treaty was ratified and the establishment of two new constituent entities in the Russian Federation was marked by a 30 gun salute under an executive order of the Russian President. The U.N. General Assembly passed a non-binding resolution that declared that the referendum was invalid, and the incorporation of Crimea into Russia as illegal.
By 1 April, around 3,000 people had fled Crimea after its annexation. 80% of those who fled were Crimean Tatars. Teams from the Organization for Security and Co-operation in Europe in Ivano-Frankivsk Oblast and Chernivtsi Oblast have assisted internally displaced persons who have resettled in western Ukraine from Crimea. Numbers of refugees, primarily Crimean Tatars, continued to rise, and by 20 May the Office of the United Nations High Commissioner for Refugees (UNHCR) said that about 10,000 people had been displaced.
2014 pro-Russian unrest in Ukraine