Manchester United captain Harry Maguire has been arrested following an incident on the island of Mykonos on Thursday.
The England defender, 27, is on holiday in Greece.
United say Maguire is "fully co-operating with the Greek authorities" following an "alleged incident".
The Syros prosecutor's office said on Friday that "three foreigners" had been arrested following an alleged altercation with police officers in Mykonos.
Maguire joined United from Leicester for £80m - a world record fee for a defender - in August 2019.
"The club is aware of an alleged incident involving Harry Maguire in Mykonos last night," United said in a statement on Friday.
"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's season finished with a 2-1 defeat by Sevilla in the Europa League semi-finals on 16 August.
