The postmaster general announced Wednesday that the U.S. Postal Service intends to halt Saturday delivery of most mailers, letters and catalogs in August, ending a 150-year tradition.

"We are simply not in a financial position where we can continue to make six-day letter delivery," Patrick R. Donahoe, postmaster general and CEO, told reporters during a morning news conference.

As CBS News correspondent Nancy Cordes reported on "CBS This Morning" Wednesday, the plan to shrink delivery from six days a week to five would only affect first-class mail while packages, mail-order medicines, priority and express mail would still be delivered on Saturdays.

Sen. Tom Coburn, R-Okla., said the move will save the struggling postal service $2 billion a year.

"It's a proper business decision and (in the) long run, good for the Postal Service and good for Americans," Coburn said.

The Postal Service has lost $41 billion during the past six years as more and more Americans turned to private shippers, email and online banking.

To save money, the Postal Service slashed hours of service at about half the nation's 26,000 post offices and trimmed its workforce by 35 percent.

But it wasn't enough. David Walker, a former government watchdog, is part of a panel looking at possible postal reforms.

Walker told Cordes the new measure "won't come close to solving the Postal Service's problem. It's got to look at more fundamental changes in its infrastructure, its compensation costs, its retirement obligations, and also what it does and who does its business."