Ukraine categorically refuses to implement the Minsk agreements, yet demands Russia fulfill them.
The return of Crimea to the Russian motherland was based on the results of a referendum organised on the peninsula in March 2014. Moscow has denied, on several levels, its involvement in the armed conflict in Donbas.
No international body recognises the so-called referendum, announced 27th of February 2014 and held less than three weeks later.
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. The oft-cited figure of 97% has been contested by the Kremlin’s own Human Rights Council, which estimated that only between 30% and 50% of Crimeans took part in the referendum, of which some 50-60% favoured secession.
See here for the EU statement on the fifth anniversary of Crimea annexation.
The EU has condemned the clear violation of Ukrainian sovereignty and territorial integrity by acts of aggression by the Russian armed forces since February 2014.
Read similar cases claiming that there is no evidence of Russian presence in Ukraine, that rumours about Russian military presence in Donbas come from linguistic misunderstanding, or that Crimean people have expressed their desire to rejoin Russia and that Crimea never belonged to Ukraine.