Russia is ready to expand the conflict area with involvement of other parties, Secretary of the National Security and Defense Council of Ukraine (NSDC) Oleksiy Danilov believes.

"The incident with the U.S. MQ-9 Reaper UAV, provoked by Russia in the Black Sea, is Putin's signal of readiness to expand the conflict area with the involvement of other parties. The all-in tactic is constantly raising stakes in the face of a strategic loss in the hope of a change in circumstances," he said on Twitter on Wednesday.