Manchester United have launched a massive bid for Napoli defender Kalidou Koulibaly.

La Repubblica says an offer of €90m was tabled by United - but immediately rejected by Napoli president Aurelio de Laurentiis.

United boss Jose Mourinho is a huge admirer of the Senegalese central defender.

Koulibaly's contract in Naples runs until 2023 and United would likely have to pay more than €100million to prise the player away from Italy.

Bayern Munich, Barcelona and Real Madrid are also credited with an interest in the player.