Quick guide to Russia-Ukraine military tensions
By Laurence Peter
image captionRussian units have been on exercises in Crimea
Sabre-rattling or preparations for war? Since mid-March, there have been many warnings from Ukraine and Western governments that Russia is massing troops in Russian-annexed Crimea and around the eastern Ukraine conflict zone.
Russia's intentions are far from clear, but here's a quick guide to the latest developments.
Is Russia preparing to invade Ukraine?
Multiple sources have reported large Russian military movements towards the eastern Ukraine border and into Crimea, which Russian forces annexed from Ukraine in March 2014. Many of these reports have appeared on Twitter, such as a Jane's intelligence analyst's tweets about Iskander short-range missiles.