The World Trade Organization said Tuesday that Trump administration tariffs on Chinese goods totaling more than $200 billion are illegal under the rules of the global trade body.
Washington has imposed levies on US$400 billion (S$545 billion) in Chinese exports. That means the United States can appeal the decision "into the void", said Timothy Keeler, a lawyer at Mayer Brown and former chief of staff for the U.S. Trade Representative.
But the U.S. responded defiantly, blasting the organisation as "completely inadequate" in holding Beijing accountable.
Trump has repeatedly criticized the WTO, which oversees worldwide disputes on trade, for allegedly treating the USA unfairly.
In a statement on Tuesday, China's Commerce Ministry said it hoped the USA would respect the rulings of the World Trade Organisation (WTO) and take practical action to maintain the multilateral trading system.
"Although the panel did not dispute the extensive evidence submitted by the U.S. of intellectual property theft by China, its decision shows that the WTO provides no remedy for such misconduct".
Tuesday's announcement marks one of the first in a series of anticipated panel rulings over complaints filed by a long line of countries over Trump's decision to slap them with steep tariffs on steel and aluminum imports.
The WTO panel ruled that the US measures violated longstanding worldwide trade rules because they only applied to products from China, and that Washington had not adequately substantiated its claim that the Chinese products hit with the extra duties had benefited from the allegedly unfair Chinese practices.
"This panel report confirms what the Trump administration has been saying for four years: The WTO is completely inadequate to stop China's harmful technology practices", said USA trade representative Robert Lighthizer in a statement.
The WTO said the USA did not provide evidence that its claims of China's unfair technology theft and state aid justified the border taxes. It also claimed the Trump administration had violated a dispute-resolution provision that requires countries to appeal to the WTO to settle disputes before slapping retaliatory tariffs on another country.
The dispute centers on the Trump administration's use of a 1970s-era U.S. trade law to unilaterally launch its commercial conflict against China in 2018.
The Trump administration has claimed the tariffs were necessary to confront China's widespread violations of intellectual property rights and forced technology transfer policies. Trade Representative Robert Lighthizer insisted the U.S. must be allowed to "defend itself" against unfair trade practices and maintained the ruling would not affect Phase I of the proposed trade agreement between the USA and China.
WTO's dispute settlement process before it triggered any retaliatory trade actions.