Manchester United say they are aware of an alleged incident in Greece involving captain Harry Maguire.
The England defender, 27, has been arrested on the island of Mykonos following an alleged altercation with police, according to media reports.
The club said in a statement on Friday: "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."
The head of the press office for the Hellenic Police's South Aegean region told the PA news agency that three men from England had been arrested on Mykonos on Thursday.
The spokesman said there had been an altercation and an exchange of words with the police, and that the three men would appear before a prosecutor on the island of Syros later on Friday.
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 Ā£80million.
In his first season at Old Trafford he was an ever-present in the Premier League, scoring one goal.
