The Guardian reports that Liverpool have been scouting the 21-year-old as manager Jurgen Klopp is looking to strengthen up front.
Williams has a €20million buyout clause in his contract that runst until the summer of 2017.
The Spain U21 international is also being tracked by the likes of Arsenal, Tottenham, Atletico Madrid and Real Madrid.
Athletic Bilabo are hoping Williams will sing a new contract believed to contain a releasue clause worth €100million.
