WASHINGTON (AP) — The financially struggling U.S. Postal Service said Wednesday it will stop delivering mail on Saturdays but continue to disburse packages six days a week, an apparent end-run around an unaccommodating Congress.

The service expects the Saturday mail cutback to begin the week of Aug. 5 and to save about $2 billion annually, said Postmaster General and CEO Patrick R. Donahoe.

"Our financial condition is urgent," Donahoe told a press conference.

The move accentuates one of the agency's strong points — package delivery has increased by 14 percent since 2010, officials say, while the delivery of letters and other mail has declined with the increasing use of email and other Internet services.

Under the new plan, mail would be delivered to homes and businesses only from Monday through Friday, but would still be delivered to post office boxes on Saturdays. Post offices now open on Saturdays would remain open on Saturdays.

Over the past several years, the Postal Service has advocated shifting to a five-day delivery schedule for mail and packages — and it repeatedly but unsuccessfully appealed to Congress to approve the move. Though an independent agency, the service gets no tax dollars for its day-to-day operations but is subject to congressional control.