The treaty sets fees that national postal services charge to deliver mail and small packages from other countries, and gives poor and developing markets lower shipping rates than developed nations.
The deal has allowed the country to flood the United States with cheap goods at shipping discounts of up to 70 percent, putting American companies at a disadvantage and straining the US mail system while fueling growth overseas, Taub said.
Officials said they hoped the notice of withdrawal would set the stage to agree on a better deal.
"President Donald J. Trump received a report from the Department of State pursuant to the August 23, 2018, Presidential Memorandum on "Modernizing the Monetary Reimbursement Model for the Delivery of Goods Through the International Postal System and Enhancing the Security and Safety of International Mail".
The relation between United States and China dates back to 1784 as they share an extreme economic relationship and the trade between two countries created positive political relations. The shipping rates under the treaty are based on weight, not value.
The UPU acknowledged on Wednesday that it had received a letter the same day from the United States to withdraw from the union a year from now.
The National Association of Manufacturers called the agreement "outdated" and said it "contributes significantly to the flood of counterfeit goods and risky drugs that enter the country from China".
The administration framed the departure as separate from the trade war in which Trump has impod tariffs on roughly half of Chinese goods entering the United States.
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"It will have dramatic consequences for American consumers".
The president argues the US loses as much as $800 billion in cash going to China every year as a result of the trade imbalance between the two countries.
The decision to withdraw from the UPU, which is now a part of the United Nations system, became the next step of the tramp against the established system of global multilateral agreements and treaties to which the us President accuses of undermining USA competitiveness.
UPU Director General Bishar Hussein said in a statement Wednesday that he "regrets the decision" and welcomed the opportunity to talk further with USA officials.
Consequently, U.S. consumers often purchase Chinese goods offered with free shipping. Trump has imposed tariffs on just over $US250 billion worth of Chinese imports coming into the U.S. and has threatened tariffs on another $US267 billion.
Under the treaty's framework it takes a year for a country to withdraw, during which rates can be renegotiated.
The Trump administration seems to be more concerned with the geopolitical implications of China's Belt and Road Initiative (BRI). "China is an energy hungry superpower and the U.S. is once again a major player on the energy export markets".