President Donald Trump today threatened to slap China with USD 500 billion worth of tariffs on the import of their products into the US.<br />'' Trump told CNBC News in an interview that he is doing this in the national interest as US has been ripped off by China for a long time. <br />'' After weeks of unproductive parleys, the US early this month slapped 25 per cent tariffs on about USD 34 billion of Chinese mechanical and technological products evoking a swift response from China which said it would hit back equally.