Dhaka, Oct. 21 -- Apple has limited customers in the United States to purchasing a maximum of two iPhone Duo devices, with its website and Apple Store app displaying a warning when buyers try to order more.

The restriction comes after pre-orders opened on Oct 16, although it remains unclear whether the limit was in place from the start.

MacRumors, a technology news website, reported the restriction after reviewing customer accounts and discussions on Reddit.

The notice tells customers that a maximum of two iPhone Duo devices can be purchased per customer and asks them to adjust the quantity before checking out.

Some Reddit users described the US limit as a new restriction, but MacRumors could not confirm whether it had applied since p...