LONDON - Russian Foreign Minister Sergei Lavrov has accused Nato, the US-led military alliance in Europe, of having "crossed a line" in its relations with Moscow, after the Western organisation announced plans to deploy additional forces in central and eastern Europe as part of the current stand-off over the fate of Ukraine.

Charging that Nato is acting with a "sense of personal superiority and personal infallibility," Mr Lavrov's accusation that the alliance is going too far in pushing Russia is the clearest indication yet that earlier hopes for a diplomatic settlement to Europe's biggest security crisis in decades are now fading, and that the danger of a military clash in the heart of the continent remains very high.