Manchester United have reportedly had an £80m bid for Napoli centre-back Kalidou Koulibaly rejected.

Koulibaly only signed a new long-term contract with Napoli in September, and his current deal does not expire until the end of the 2022-23 campaign.

Last month, it was reported that Barcelona were prepared to pay £88m to sign the Senegal international, who is believed to be a transfer target for a number of Europe's biggest clubs.

United boss Jose Mourinho has reportedly identified Koulibaly as the perfect player to improve his defence, which has already conceded 21 times in the Premier League this season.

According to La Repubblica, United launched an £80m bid for the defender, but were told by Napoli that it would take an offer in the region of £89m to convince the Italian club to sell.

United were linked with a number of centre-backs during the recent summer transfer window, but Mourinho was ultimately left frustrated.