Manchester United have been made aware of an “alleged incident” involving captain Harry Maguire in Mykonos on Thursday night.
The England defender, 27, has been transferred from Mykonos to Syros in a police vehicle on a ship after reportedly being arrested following the alleged incident.
Police in Greece are continuing their investigation into the matter.
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.”
United players are taking time off after their Europa League exertions earlier this month. The club were eliminated by Spanish side Sevilla last Sunday.
Maguire is the world’s most expensive defender, having signed for United from Leicester last summer for £80m.
In his first season at Old Trafford he was an ever-present in the Premier League, scoring one goal.