Manchester United have reportedly decided to up their efforts to sign Napoli defender Kalidou Koulibaly.

United are known to be in the market for a new centre-back, and it has been alleged that Leicester City's Harry Maguire could be targeted ahead of next season.

Koulibaly is another player who has been heavily linked with a move to Old Trafford, and according to La Gazzetta dello Sport, United are planning to make a big-money offer.

The report claims that United are eager to tempt Napoli into selling one of their key men, who still has just over four years remaining on his contract.

Napoli could potentially demand in the region of £100m, with the Senegal international having recently penned an extension to his deal.