President Donald Trump’s trade war with China has escalated even as other countries got a partial reprieve, threatening the relationship between U.S. manufacturers and retailers and one of America’s largest trading partners.

China has appointed a new trade negotiator in the midst of its tariff fight with the United States as the world’s two largest economies steadily increase tariffs on each other’s goods.

China on Wednesday unexpectedly appointed a new trade negotiator key in any talks to resolve the escalating tariff war with the United States, replacing trade tsar Wang Shouwen with its envoy to the World Trade Organization.