Manchester United have a fitness scare over Paul Pogba ahead of Sunday's derby at the Etihad Stadium.

Pogba was unable to train with the rest of United's squad on Friday and instead forced to work indoors after suffering what has been described as a "little injury".

It is unclear at this stage if the France midfielder is in danger of missing the trip to Manchester City or when the problem occurred.

United trained at 3pm on Thursday afternoon following their return from Turin where they beat Juventus 2-1 in the Champions League on Wednesday. Manager Jose Mourinho has another training session planned for Saturday.

Alexis Sanchez trained on Friday despite the Chile striker suffering a minor thigh injury against Juventus. Romelu Lukaku has missed United's past two matches against Bournemouth and Juventus through injury but the Belgium striker underwent some light training on Wednesday and Thursday and trained again on Friday.

Mourinho wants to see how Lukaku responds on Saturday before deciding whether to include him in his squad.

Earlier on Friday Mourinho vowed to go toe-to-toe in Sunday’s derby with a Manchester City side that he claims are “untouchable” in terms of the quality of their football and the squad they have built.