International law experts have repeatedly denied the claim that Crimea has been annexed.
Recurring pro-Kremlin narrative on the illegal annexation of Crimea.
No international body recognises the so-called referendum, announced on 27th of February and held three weeks later on 16th of March 2014.
On March 27th, 2014, the UN General Assembly adopted a resolution in which it stated that the referendum in Crimea was not valid and could not serve as a basis for any change in the status of the peninsula.
A year after the illegal annexation, Russian President Vladimir Putin admitted that the plan to annex Crimea was ordered weeks before the so-called referendum.
The Office of the Prosecutor of the International Criminal Court stated that “the information available suggests that the situation within the territory of Crimea and Sevastopol amounts to an international armed conflict between Ukraine and the Russian Federation. This international armed conflict began at the latest on 26th February when the Russian Federation deployed members of its armed forces to gain control over parts of the Ukrainian territory without the consent of the Ukrainian Government".
For the EU statement on the fifth anniversary of Crimea annexation see here.