Neither Fifa nor Russia has said which stadiums are in danger of being cut .
Mutko has previously said that stadiums in the western city of Kaliningrad and southern city of Volgograd are proving the most difficult to construct .
Neither Fifa nor Russia has said which stadiums are in danger of being cut , although Mutko has previously said that stadiums in the western city of Kaliningrad and southern city of Volgograd are proving the most difficult to construct .