As Russia celebrated what it terms its "reunification" with Crimea, NATO hit out at Moscow over its plans to further militarise the Black Sea.

The annexation of Crimea in March 2014 and Russia's role in the Ukraine conflict sent ties between NATO and Moscow plunging to post-Cold War lows.

NATO said there would be no return to "business as usual" with Moscow until there was a "a clear, constructive change in Russia's actions".

"We condemn Russia's ongoing and wide-ranging military build-up in Crimea, and are concerned by Russia's efforts and stated plans for further military build-up in the Black Sea region," NATO's ruling North Atlantic Council said in a statement.

The statement said NATO would never recognise Russia's annexation of Crimea and urged Moscow to return the territory to Ukraine.