UPDATE: See the official statement from the USPS here.

The Associated Press is reporting that the U.S. Postal Service is discontinuing delivery of first class mail on Saturdays by Aug. 1. Priority mail and packages will still be delivered six days per week.

According to a set of FAQs (from 2011) found on the USPS website, the move is caused by:

A crushing economic recession combined with increased use of the Internet has caused mail volumes to drop from 208 billion pieces in ‘08 to 177 billion pieces in ’09, a 12.7 percent decline and a long way from the high water mark of 213 billion pieces delivered in 2006... Our current business model of delivering mail six days a week is no longer sustainable. We must change in order to remain an integral part of the American community for decades to come.

That same FAQs page estimates that "about $3.1 billion can be saved the first year the Postal Service switches to five days of delivery, with savings projected to be as much as $5.2 billion annually by 2020." Most news sources are placing estimates closer to $2 billion.

While customers may not receive letters on Saturdays, the USPS isn't ready to give up its place in the parcel delivery market to its two top competitors, UPS and FedEx.

Under the plan, Saturday delivery to post office boxes will continue. In addition, those post offices currently offering Saturday hours will continue to operate on a six-day schedule.

The Postal Service has long eyed five-day mail delivery, but has been unsuccessful in changing operations until this point. It is not immediately clear how the agency will cease Saturday deliveries without congressional approval.

Nearly seven in 10 Americans are in favor of the move as a cost-cutting measure, according to an AP report.