PORTLAND — A dispute with the U.S. Postal Service over its plans to move a mail distribution center has Maine’s U.S. senators concerned.

The service angered landowners, community leaders and hundreds of workers when it announced it would move to the Lewiston-Auburn area. Since then, the service has said it will reconsider sites in the Portland area.

Sens. Olympia Snowe and Susan Collins, both Republicans, are asking the U.S. Postal Service to explain in detail its site review and selection process. They said they want to make sure the selection process is fair.

They have asked the postmaster general to provide a complete explanation of the site selection process and steps taken thus far in finding a new site for the center, now in Portland.

The Postal Service is pitting communities against one another with the way it has been handling relocation, they said in a joint statement Wednesday.

“It is imperative that the Postal Service demonstrate sensitivity to the concerns of both communities,” the senators said. “Unfortunately, the mixed messages from, and confusing steps taken by, the Postal Service have exacerbated concerns in both communities, and have severely undermined public confidence in the process.”