Gundogan, who was linked with a move to the Premier League in the summer, said that he would provide no information on the progress of talks until he agrees terms.
"There is nothing new to comment on, those talks and negotiations are actually ongoing," Gundogan told Ruhr Nachrichten. "If we had anything to announce, we would reveal it.
"I am not going to make statements on the contents of those talks. Everyone has to be patient about it, just like I have to be patient in terms of my current injury."
Gundogan has made 57 first-team appearances for Dortmund.