Apple (NASDAQ:AAPL) fans around the world are eagerly waiting for the company to release its new iPhone 5s on Friday, but they might be in for a disappointment considering that new reports have surfaced, citing Apple’s carrier partners, to say that the handset’s inventory could be extremely limited at launch.

According to a report from AllThingsD, an unnamed carrier will have “grotesquely unavailable inventory” of the iPhone 5s on the device's release date, while another carrier also complained about disappointing shipments of the new handset from Apple. The second carrier also said that the demand for the flagship iPhone 5s could be less than previously expected.

BGR reported on Thursday that Apple could not produce enough iPhone 5s units to meet the initial demand. The report quoted one of its sources as saying that the iPhone 5s supply is “severely constrained,” stating that as the reason why Apple and its partner carriers did not offer per-orders for the device.

According to another report, from 9to5Mac, which corroborates the AllThingsD story, white/silver and white/gold models of the iPhone 5s could be difficult to come by on the day of the launch.

The 9to5Mac report said that the Space Gray model of the handset is expected to be the most popular version among consumers, with an average three out of four iPhone 5s units to be delivered to Apple Stores for the launch on Friday expected to be a Space Gray model.

Apple also is said to be concerned about the supply constraints and the company is reportedly preparing an update for its Apple Store app, which will allow users to see if and when new iPhone models will be available at their local stores.

Apple has confirmed that authorized retail stores will begin selling the iPhone 5s on Friday at 8 a.m. local time in the respective time zones, while the phone will hit the company’s online store for purchase on Sept. 20 at 12:01 a.m. PDT (3.01 a.m. EDT).

On the other hand, the company's other new product -- the iPhone 5c -- which is available in multiple colors, has reportedly attracted more consumer interest and is not plagued by the supply issues bothering the iPhone 5s.

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