China's ambassador to the WTO Li Chenggang was speaking at a WTO meeting on trade disputes shortly after the United States lodged an appeal against a recent WTO ruling which found that U.S. metal tariffs breached global rules.

"These troubling behaviors of the U.S. have clearly depicted an image of the U.S. as a unilateral bully, a rule breaker, and a supply chain disruptor," he said, according to a copy of his speech obtained by Reuters.

The WTO has made important rulings against the United States in recent weeks, including the metals ruling involving China and a separate dispute with Hong Kong over labeling. Washington, which has long criticized the WTO dispute system for overreach and is leading discussions on reforming it, has criticized both rulings.

However, the WTO will not be able to review Washington's appeal of the metals case because its top appeals bench is paralyzed after the United States blocked new judges.

"China would have hoped that the U.S. would show due self-restraint not to appeal every unfavorable panel report into the void, which the U.S. itself has created," Li added.