Ukraine's richest oligarch has come down firmly on the side of Kiev authorities, calling on thousands of workers at his plants across the east to attend workplace protests against the armed separatist movement in the east of the country.

In a video address released late on Monday, Rinat Akhmetov appeared emotional and angry, and after months of equivocating between the separatists and the new Kiev authorities, launched a savage attack on the armed rebels, who have declared independence from Kiev as the Donetsk People's Republic.

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