WASHINGTON — The U.S. Postal Service said Monday it wants to end Saturday mail delivery by early next year as part of a wide-ranging plan to slash jobs, save billions of dollars and cope with the effect of declining mail volume in the Internet age.

“”Given the fact that we’re facing such a huge deficit, we’d like to move as quickly as possible,”” Postmaster GeneralJohn E. Pottertold a news conference.

Faced with a projected $238-billion deficit over the next decade, the Postal Service board of governors approved the cuts last week and ordered Potter to submit the proposal to the Postal Regulatory Commission on Tuesday. In addition to cutting one day a week from the delivery schedule, the proposal would eliminate the equivalent of 49,000 full- and part-time jobs.

Officials said the changes would save the Postal Service a forecasted $3.3 billion in the first year and about $5.1 billion annually by 2020.

Under the plan, letter carriers would stop street deliveries to U.S. homes and businesses and pickups from blue collection boxes on Saturdays. Mail would continue to be accepted at post offices Saturday, to be processed Monday. Express mail and remittance mail services would continue seven days a week.

If approved by the Congress and the regulatory commission, officials said they hoped to implement this plan by the first half of 2011. Congress currently mandates delivery to all U.S. addresses six days a week.

Potter said the Postal Service would eliminate about 26,000 positions through employee attrition and lay off 13,000 part-time workers, most of whom carry the mail once a week as substitutes. He said the high attrition rates are only possible because the average age of letter carriers is 53 and most have pension arrangements that would allow them to retire at 55. About 10,000 carriers retire each year, Potter said.

Potters said the changes were made necessary by citing continuing drops in mail volume. American mailboxes currently receive an average of four pieces of mail each day, but this is projected to be reduced to three pieces by 2020. Current daily revenue generated by each delivery is $1.40 but will slide to about $1 per delivery in 2020.