New Delhi, June 21 -- Apple has permanently closed three retail stores in the United States, including its first-ever unionized location, marking a rare contraction of the company's vast retail network and igniting fresh debate over labor relations and the future of mall-based Apple Stores.

The closures took effect on June 20, affecting Apple Towson Town Center in Maryland, Apple North County in California, and Apple Trumbull in Connecticut. Apple said the decision was driven by deteriorating conditions at the malls where the stores operated and the departure of major retailers from those shopping centers.

While Apple routinely renovates, relocates, and expands stores worldwide, outright permanent closures remain unusual for the company...