The two men have been at loggerheads for much of the season, with television cameras picking up a frosty exchange during training at Carrington on Wednesday morning following defeat to Derby County in the Carabao Cup the night before.
Mourinho admitted only three points would suffice in Saturdays Premier League match away to West Ham, but they left the London Stadium with a 3-1 defeat.
Pogba was withdrawn with 20 minutes remaining, and United two goals down, and made minimal eye contract with Mourinho as he made his way to the bench.
The Portuguese coach also gave a terse reply when asked about the midfielders unspectacular display, saying only: He tried hard.
And now The Mirror claim Pogba – who was also stripped of his second captain status – has told teammates he no longer wishes to play for Mourinho if he allows their conflict to escalate any further.
Pogba is unhappy with the way Mourinho is conducting himself and managing United, and has said to teammates that he is prepared to go all the way to get rid of Mourinho by refusing to play under the Portuguese if the atmosphere does not improve.
That would put United executive vice-chairman Ed Woodward under enormous pressure to choose between his manager and his record signing.
Woodward is still believed to back Mourinho, though the latest defeat to West Ham has been a tough pill to swallow, and Pogba is increasingly prepared to try and force his hand.
More: Manchester United FC