In a joint statement, the diplomacy chiefs of the Baltic states, Poland, Sweden, Denmark, Romania and Ukraine emphasized that the annexation of Crimea and Russia's continued aggression in Donbass violated the European security regime and principles, which have facilitated European stability and security since the end of Cold War.

"What happened in Crimea is not just about Ukraine, it concerns us all. That is why we will neither forget nor abandon Crimea (…). We will not allow Crimea to slip off the international agenda,"reads the letter published in EUobserver and other media.

The ministers also called upon the international community to speak up about human rights violations in Crimea.

Russia annexed the Crimean peninsula in March of 2014 after Moscow-supported Ukrainian president Viktor Yanukovych was overthrown in Kiev.