Keane and Berbatov both scored 15 league goals last season
Tottenham have submitted a year's worth of evidence to the Premier League to support their complaint over Manchester United's pursuit of Dimitar Berbatov.
A newspaper report quoting United boss Sir Alex Ferguson as saying he expected to sign the striker is understood to be only one of Spurs' concerns.
Ferguson denies making the comments, but the Londoners believe United have broken Premier League rules.
Spurs have also reported Liverpool for their public courting of Robbie Keane.
The next step will see the Premier League board write to all parties before deciding whether to take further action.
I have absolutely no wish to sell either player and to date we have not accepted any offer for either
Tottenham chairman Daniel Levy
Last week, Tottenham chairman Daniel Levy accused United of being hypocritical, given that the European Champions reported Real Madrid to governing body Fifa because of their interest in Portugal winger Cristiano Ronaldo.
Levy said: "The behaviour of both clubs has been disgraceful. We told both clubs very early on that we had no interest in selling Robbie or Dimitar, respectively, and that they should refrain from pursuing the player.
"Both clubs arrogantly chose to ignore this request and we now have evidence that both clubs have systematically been working to prise the players away from us, outside of Premier League rules of conduct."
A national newspaper claimed on 18 July that United had made Tottenham an offer for 27-year-old Berbatov and alleged that Ferguson was confident a deal would go through.
Benitez admitted earlier this month that he was interested in bringing striker Keane, 28, to Anfield this summer.
But it was Ferguson's reported comments that prompted Levy to speak out about the attempts to unsettle his strikers.
"The public comments by Manchester United's manager, announcing that he has made an offer for Dimitar and is confident that the deal will go through with time working in their favour, is a blatant example of sheer arrogance and interference with one of our players," he said.
"It is also probably one of the worst offences by any manager in the Premier League to date.
"As a result, we have made an official complaint to the Premier League about the conduct of Manchester United.
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