Man United say they are aware of an alleged incident.
Manchester United say they're aware of an "" involving captain Harry Maguire in Mykonos.
Local news outlet OEMA say Maguire was involved in a heated row with British tourists during a night out.
The 27 year old England defender is reported to have been arrested after the incident.
Manchester United said in a statement: "The club is aware of an alleged incident involving Harry Maguire in Mykonos last night.
"Contact has been made with Harry, and he is fully co-operating with the Greek authorities.
"At this time we will be making no further comment."
Maguire's fiancee, Fern Hawkins, posted a picture of the pair in Mykonos on her Instagram page on Thursday night.
