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.

Despite comments from U.S. President Donald Trump that he's spoken with Chinese President Xi Jinping about tariffs, China maintains that no talks have taken place.

China appears to have quietly rolled back retaliatory tariffs of 125% on some semiconductors made in the United States, according to details provided to CNN on Friday by three import agencies in the southern technology hub of Shenzhen.