The young Dutchman has been linked with both Premier League clubs.
"I cannot say at the moment if it is serious interest, an enquiry, or just rumours. We are waiting for calls from both clubs, as we need an official offer from Liverpool or Spurs to proceed.
"He is eager to move and he finds Tottenham and Liverpool both very interesting opportunities. In the game against Liverpool he got injured, and he is still a couple of weeks off being fully fit, but everything has gone well.
"But as I said, I have not had an offer from either club, so we are waiting."