Satellite images released by Nato's military command, the Supreme Headquarters Allied Powers Europe (Shape), appear to show a build-up of Russian tanks, armoured vehicles, combat jets and helicopter gunships stationed near Russia's eastern border with Ukraine.
BBC: Russian military build-up near Ukraine
Russian soldiers prepare to fire their Msta-S self-propelled howitzer during military exercises in the southern Russia's Volgograd region, on April 2, 2014.
