Southampton have asked the Premier League to investigate an alleged illegal approach from Liverpool for Virgil van Dijk, Press Association Sport reports.
PA Sport reports Southampton are yet to receive any contact from Liverpool regarding Van Dijk, despite sources telling ESPN FC that the defender has indicated he is eager to move to Anfield.
Jurgen Klopp has made Van Dijk, who has also been linked with Chelsea and Manchester City, his top target this summer but Saints have reportedly been irritated by what they see as an attempt to unsettle their player and are ready to reject an official offer.
The Daily Echo reports the decision to report the matter to the Premier League came after the Southampton hierarchy met on Tuesday morning.
Last month, Southampton chairman Ralph Krueger told PA Sport the club could turn down even a £60 million bid for Van Dijk.
"Can we? Yes," Krueger said. "We do not need to sell any player for the first time since I've been here."
Former Celtic player Van Dijk, 25, signed a six-year contract 11 months ago but made only 21 Premier League appearances last term after missing the second half of the season with an ankle ligament injury.
The Netherlands international is the latest in a long line of Southampton stars to catch the eye of Liverpool, who have signed Sadio Mane, Nathaniel Clyne, Rickie Lambert, Adam Lallana and Dejan Lovren from St Mary's, all in the last three years.