The highly-rated Brazilian defender has been strongly linked with a move to the Qatari-back Ligue 1 side the past week.
Speculation has been mounting that the French outfit are preparing to offer in excess of £40 million for the Selecao star.
However, with the 27-year-old believed to be in Paris waiting to undergo a medical, it now appears the Rossoneri want to keep hold of Silva.
"Berlusconi intends to resist all offers from PSG for Thiago Silva," Galliani told Sky Italia.
PSG sporting director Leonardo added: "There is no agreement.
"Many details have not been defined but this is normal considering the type of deal we are talking about.
"We will wait and see but I don't think the negotiations will take very long."
Thiago Silva has also been the subject of speculation regarding a part-exchange deal involving Barcelona midfielder Thiago Alcantara.
Get the best features, fun and footballing frolics straight to your inbox every week.
Thank you for signing up to Four Four Two. You will receive a verification email shortly.
There was a problem. Please refresh the page and try again.