BEIJING (AP) — China says it regrets Washington's decision to leave the United Nations treaty that regulates international postage amid a worsening trade dispute between the world's top two economies.

Foreign Ministry spokesman Lu Kang said Thursday the move should not be linked to China, despite arguments that the arrangement especially benefits Chinese manufacturers by making it cheaper to ship packages from Beijing to New York than from San Francisco to the U.S. East coast.

President Donald Trump says the 144-year-old Universal Post Union puts U.S. businesses at a disadvantage and is used by shippers of the narcotic fentanyl to the U.S. from China.

The move comes as the U.S. has imposed tariffs on $250 billion in Chinese goods and Beijing has retaliated by targeting $110 billion in U.S. products.