• The US Postal Service
  • Amazon
  • openly criticized Amazon's dealings

The US Postal Service is hiking prices for its service utilized by Amazon after facing months of criticism from President Donald Trump.

On Wednesday, the USPS proposed a price increase of 12.3% for its lightweight parcel select service. Non-lightweight parcel select prices would increase by an average of 9.3%. The proposed price hikes would go into effect in January 2019 if they are

Parcel select is used by Amazon, as well as companies such as FedEx and UPS, for "last-mile" package delivery, CNBC notes. The USPS' low fixed costs and mandate to deliver mail to Americans make it an ideal option to get a package from a fulfillment depot to its final destination.

Trump has criticized Amazon's deal with the USPS for months.

"The Amazon Washington Post has gone crazy against me ever since they lost the Internet Tax Case in the U.S. Supreme Court two months ago," Trump tweeted in July. "Next up is the U.S. Post Office which they use, at a fraction of real cost, as their 'delivery boy' for a BIG percentage of their packages."

ordered the formation of a task force