Japan’s economy risks taking another hit if US President Donald Trump slaps fresh tariffs on China, sparking a renewed US-China trade war, according the government’s chief economist.

President Donald Trump on Thursday warned off BRICS member countries from replacing the U.S. dollar as a reserve currency by repeating a 100%-tariffs threat he had made weeks after winning the November presidential elections.

Trump has threatened still more tariffs, proposing 25% on goods from Mexico and Canada, an additional 10% on China and 25% on Colombia after that country initially refused deportation flights from the U.