The official also indicated that training at courses that have started are to be carried out according to the standards and methodology of the US Armed Forces undertaken in Iraq and Afghanistan.
"According to information received from a source in the Armed Forces of Ukraine, Ukraine's military and political leadership is preparing to regain control over the lost territories," the source said. "Police training for filtration and clearing of territories is carried out in line with US Army standards using methodology materials compiled by the US military."
The American standards were relayed through slides that included displays of both the American and Ukrainian flags with the inscriptions "Fearless Guardsman" and "Strong army, strong Europe." Names of US instructors were also included.
Some 11 training manuals had been provided to Russian security forces, with files ranging on evacuating the injured from the battlefield, ground sweeping, visual identifications of improvised explosive devices to countering drones, among other topics.
The official also stated that Ukrainian forces at training camps were also being trained on combating sabotage and reconnaissance groups, as well as the underground.
News of the findings come after regional authorities announced that Ukrainian troops would not be allowed to enter the city of Kherson despite the West's push for Kiev to implement military operations.