The U.S. Postal Service is launching a major review of up to 3,600 post offices across the country for possible closure as it shrinks its network in light of declining mail volume.

On Tuesday, Postmaster General Patrick Donahoe will release a list of post offices to be studied for closing, as well as announce “a new concept” for possibly replacing them, postal officials said Wednesday.

The Postal Service is expected to file a request with regulators within days for a formal opinion on the review.

Spokesman David A. Partenheimer declined to provide details on the review, but in an interview with The Washington Post’s editorial board earlier this week, Postal Regulatory Commission chairman Ruth Goldway said the number of post offices under scrutiny would be close to 3,600. Goldway said she expects some areas of the country to have more closures than others.

The review comes weeks after the Postal Service published the final version of regulations aimed at making it easier to shutter some of its 32,000 post offices. Despite some changes to the draft released in March, the final version preserved a key element allowing the Postal Service to target facilities that suffer from “insufficient customer demand” or where customers have other options for buying stamps and postal services.

Since March, Donahoe has floated a couple of numbers on how many facilities he wants to close within the next year. The initial figure was around 2,000, but it then fell to 1,000. Whatever the size of the upcoming hit list, it’s likely to shrink substantially. Two years ago, the Postal Service began studying the possibility of closing as many as 3,200 post offices. The actual number going out of business? About 140.

In today’s Federal Diary, Donahoe says postal employees are now receiving the first of several video messages from him about the state of the Postal Service. Given the dire situation, Donahoe’s message isn’t exactly a pep talk.

“We are a business. You work in a business,” Donahoe says in a video sent to postal workers Wednesday.

“We are no different than any other business out there,” he says in the video. “You have to have revenue. If you don’t have revenue, you got to get the cost down. It’s that simple. There’s nobody that’s going to come in here with a bucketload of money to make up that difference.”

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