FEARS of a US invasion of Ukraine’s breakaway Donbass region have been raised amid allegations that the controversial Blackwater private security company — since renamed Academi — is training mercenaries for the task.

Deputy chief-of-staff of the Donetsk People’s Republic militia Eduard Basurin said US instructors had been spotted in a far-right training camp in the Sumy region of north-eastern Ukraine over the weekend.

“The Sumy branch of the National Corps radical organisation has embarked on training its mercenaries under the supervision of nationalists who have combat experience in the 2014 Donbass punitive operation.