China has exempted some U.S. imports from its 125% tariffs and is asking firms to identify critical goods they need levy-free, according to businesses notified, in the clearest sign yet of Beijing's concerns about the trade war's economic fallout.

China has not communicated publicly on any exemptions. Despite comments from U.S. President Donald Trump saying that he's spoken with Chinese president Xi Jinping about tariffs, China maintains that no talks have taken place.

An American business group said that Chinese officials had been surveying companies about American products that are crucial to their supply chains.