KIEV, June 5 - The Vostok Battalion, a Russian intelligence-linked Chechen-founded paramilitary consisting of battle-hardened militants from the most restive regions within Moscow's orbit, has arrived to take charge of Ukraine's pro-Russian rebels, Business Insider reported Thursday.

On May 30, Vostok took over rebel headquarters in Donetsk, asserting control over less-disciplined separatist militants. According to the New York Times today, the group, which became active in Ukraine in early May, has even set up a training camp in Donetsk's botanical gardens.