Three weeks before Ukraine's army forced rebel fighters out of the strategic eastern city of Slaviansk, their commander made a desperate plea for military help from Russia.

"A week will pass, two, three, maybe a month, and the rebellion's best fighters will be bled dry and, sooner or later, crushed and destroyed," Igor Girkin, who is better known as Strelkov, said in a comments widely viewed online.

The appeal was met with silence by President Vladimir Putin, and on Saturday, as if on cue, Girkin's outnumbered and outgunned forces abandoned the city after weeks of shelling.