De Jong is the subject of intense interest from Manchester United, while Dembele is current off contract.
“There is no date for Dembélé. If he doesn't accept our proposal, he won't be able to stay. If he does not accept it, there is nothing to do.
"You have to respect the salary structure that you want so that there is no imbalance that could distort everything. And it's the same with Frenkie. And with the reinforcements coming.
"We are in no hurry, even if we know that we cannot delay too long so as not to hinder the arrival of other players who have understood the situation. We will move forward in the transfer window with this principle."