The company is expected to say the changes will go into effect in August in an announcement that is scheduled for late Wednesday.
The cuts, which will end a 150-year long tradition of Saturday delivery, came after the USPS reportedly lost $16 billion last year as more Americans have turned to private shippers, email and online banking, CBS news noted.
According to Sen. Tom Coburn, R-Okla., the shift will save the company about $2 billion a year. "It's a proper business decision and [in the] long run, good for the Postal Service and good for Americans," he said.
The USPS has been struggling for a long time, and even with their past efforts to cut service hours in 26,000 offices and to lay off 35 percent of its workforce, the company has lost $41 billion over the past six years.
Over the past five years the Postal Service has unsuccessfully appealed to Congress for a switch to a five-day delivery model. It is not yet clear how they will eliminate Saturday mail without Congress' approval, CS Monitor noted.
Coburn told CBS that the move wasn't an attempt to force Congress to take action, but a desperate act for survival.
"They're in survival mode," he explained. "You're not going to have any post office. I mean, here's the alternative: They're losing $25 million dollars a day. A day. They have to do something."