Is Amazon preparing to open hundreds of bricks and mortar bookstores? This is the question swirling in the media after a comment made by the head of a mall operator during a conference call on Tuesday.

While discussing the fourth quarter results of General Growth Properties, CEO Sandy Mathrani said it is his understanding that Amazon has plans to open between 300 and 400 physical bookstores. The comment has now sparked widespread speculation in the publishing industry about the etailer's plans.

Mathrani's statement came in response to a question about mall customer traffic, but Amazon itself has not responded to inquiries about the expansion. When asked whether Amazon does indeed intend to open up to 400 physical bookstores, an Amazon spokesperson said the company does not comment on "rumors and speculation."

Asked if Mathrani had firsthand knowledge of Amazon's plans or could elaborate on his remarks, Kevin Berry, v-p of investor relations for General Growth, said the company did not have any comment beyond the remarks made by Mathrani during the conference call.

Amazon opened its first bookstore, Seattle's Amazon Books, in December 2015. Shortly after the location opened, Amazon Books v-p Jennifer Cast told PW she hoped the company would launch more stores, but gave no indication of a specific growth plan.

Mathrani's remarks were first reported by the Wall Street Journal.