Manchester United are firming up their interest in Napoli defender Kalidou Koulibaly.

Il Mattino says United are in pole position to land Koulibaly.

But there are several clubs in the frame with Arsenal, Tottenham and Chelsea also named as interested parties as they aim to strengthen their defences.

It is claimed a move for Koulibaly could rest on Napoli's form over the closing stages of the season.

If they miss out on qualification for European qualification, then they could be forced to sell to cover the shortfall from lack of prize money.

They are currently 10th in the Serie A table with 30 points.