Manchester United have made a world-record bid for Napoli defender Kalidou Koulibaly , according to the latest reports from Italy.

Boss Ole Gunnar Solskjaer needs to shore up his defence if he is to get his Manchester United side back to the top of English and European football.

United have long been linked with 27-year-old Senegal centre-back Koulibaly, as well as Tottenhamdefender Toby Alderweireld.

And it has now been claimed that United made a bid of €105million (£90m) for Koulibaly late last month.

That would dwarf the current record fee for a defender - the £75m Liverpool paid for their star performer of this season, Virgil van Dijk.