Southampton has asked the Premier League to investigate an apparent illegal approach from Liverpool to Virgil van Dijk, according to Sky Sports.

The Saints have sold several players to Liverpool over the past few seasons, including Adam Lallana, Sadio Mane and Dejan Lovren.

However, it is understood that this time around Southampton are sceptical over Liverpool's actions and have enquired to the authorities to investigate the situation further.

Liverpool is reportedly prepared to pay £60m for the Dutch defender.

But Southampton is also adamant they can keep the 25-year old, who still has five years left to run on his contract.