UNDATED (WJON News) -- Several Minnesota lawmakers are demanding answers from the U.S. Postal Service after complaints about delivery delays and staffing shortages.

Senators Amy Klobuchar and Tina Smith and Congresswoman Angie Craig have all asked the Postmaster General to explain what's causing the complaints and what he plans to do about it.

Craig says four post offices in the Twin Cities area are now being audited by the postal service after receiving complaints.

Senator Smith says she's also heard complaints from parts of northern Minnesota, where postal service workers have allegedly been told to emphasize Amazon packages over regular mail.

Smith says she's also directed questions to the postal service but has received unsatisfactory answers.