Twente president Joop Munsterman admits there is interest for his striker and that the club may not be able to stop him from leaving.
Liverpool are favorites for the Dutchman.
Munsterman said: "We want to keep Luuk. He is a vital player if we want to win the championship again next season and when we play in Europe.
"We have said that we won't go lower than £12.5m as a transfer fee. We need a top price for a top player.''