Liverpool chiefs are angry over accusations of "borderline xenophobia" from Manchester City aim at their manager Jurgen Klopp.
The Daily Mail says before Liverpool ended City's unbeaten start to the season on Sunday, Klopp had claimed: "There are three clubs in world football who can do what they want financially."
The German was assumed to be referring to City, Newcastle United and Paris Saint-Germain, all of whom have owners from the Middle East.
It drew an angry response from the Premier League champions, who believe Klopp inflamed the toxic rivalry between the clubs. Liverpool are understood to be enraged by the accusation from City.
Mohamed Salah's 76th-minute goal proved the winner but the match had already turned ugly. City supporters chanted songs about stadium tragedies and the club's manager, Pep Guardiola, was targeted by three coins thrown from the home crowd. There were also allegations from City that their team bus was attacked after the game.