Russia has not seized Ukrainian territory. Russia is not in Ukraine at all.
Russia violated international law as well as key principles of the European security framework in illegally annexing the Autonomous Republic of Crimea and the City of Sevastopol. The European Union does not recognise and continues to strongly condemn this violation of international law, which remains a challenge to the international security order. This position is based on the UN Charter, which clearly states that the territory of a State cannot be acquired by another State resulting from the threat or use of force, as well as on the Helsinki Final Act in which the signatories declared their intention to respect the inviolability of frontiers and territorial integrity: http://bit.ly/2d9uXT9. UNGA Resolution 68/262, which condemned Russia's illegal actions in Ukraine, was supported by 100 United Nations member states. Only 10 states opposed it. http://bit.ly/1RZGnjo. President Putin himself admitted to the presence of Russian “people there, who deal with certain matters, including in the military area” [aka soldiers] in December 2015 http://bit.ly/1kC94ch and again in October 2016 http://bit.ly/2enbpt2.