The United States agreed on Wednesday to stay in a United Nations body that has regulated international mail service for more than a century after delegates agreed during emergency talks to change the way postal fees are structured....

The deal struck on Wednesday will allow the United States to start setting its own postal fees in July and allow other countries that receive more than 75,000 metric tons of mail a year to start phasing in higher rates in January 2021....

Delegates from about 140 countries stood to applaud as Bishar Hussein, the head of the Universal Postal Union, said the new formula had passed. Only a day earlier, he had warned that a United States withdrawal could lead to chaos in international mail service....

Peter Navarro, President Trump’s trade adviser, said the decision was a “huge victory for millions of American workers and businesses” and would save the United States between $300 million and $500 million a year.