On Monday, AT&T, the giant American telecommunications services provider, resumed the online sale of Apple's iPhone to residents across the city of New York, after temporarily blocking sales for people in the area recently, but the reason behind the move has still remained a mystery.

Over the weekend, people looking to buy Apple's smartphone in the area received a message from AT&T which said that the device was not available in their region, as soon as they entered the New York City zip code. The iPhone, however, was still available to the area's residents through the AT&T store.

Starting Monday, although, New Yorkers could once again purchase the phone via the firm's official website.

When asked about the move, AT&T declined to comment or give an elaborate reason, but a spokesperson did say, "We periodically modify our promotions and distribution channels".

One major reason for the cutback on sales, which lasted for some time, could be that like many other major telecom companies, AT&T is trying to curb the increasing data usage by users of smartphones. Up until now, AT&T is the exclusive iPhone carrier in the country.