WASHINGTON — The financially beleaguered Postal Service announced Tuesday that it would consider closing more than 3,600 of its 32,000 post offices.

Continuing efforts to reduce costs by shrinking the organization’s retail network and work force, Postmaster General Patrick Donahoe released a list of the targeted offices, which are primarily in rural locations and produce little revenue. There will be a 60-day comment period before the Postal Service makes a final decision, which can be appealed to the Postal Regulatory Commission.

In communities that lose post offices, the Postal Service may outsource basic services, like selling stamps and shipping flat-rate packages, to local businesses like pharmacies and groceries, Mr. Donahoe said.

“The Postal Service of the future will be smaller, leaner and more competitive,” he said in a statement.

The Postal Service, which relies primarily on its own revenue, is expected to lose more than $8 billion this year and has maxed out a $15 billion loan from the Treasury. Mail volume has dropped 20 percent in the past four years, and about 200,000 career positions have been eliminated in the past decade.

“This is bitter medicine, but changed times call for a changed Postal Service,” said Art Sackler, chairman of the Coalition for a 21st Century Postal Service, which represents mailing-dependent industries like pharmaceutical delivery and magazines.

The potential closings involve offices in every state except Delaware, home to Senator Thomas R. Carper, who has put forth one of five bills introduced in Congress that would overhaul the Postal Service. Mr. Carper’s bill most closely aligns with what the Postal Service wants, including provisions that would allow for elimination of Saturday deliveries and refunding of surpluses in postal retirement accounts.

A Carper spokeswoman said Tuesday that the senator did not communicate with the Postal Service about potential closings and that Delaware’s absence on the list was a “fluke.”