>> julie: this is a fox news alert. china saying it will not hesitate to fight back with a, quote, major response after president trump threatened tariffs on another $100 billion worth of chinese goods. escalating trade tensions between two of the world's biggest economies, sending the dow plummeting again on friday, closing down over 500 points. this after treasury secretary steven mnuchin said there is, and i'm quoting, the potential of a trade war and just moments ago the president tweeting this. the united states hasn't had a trade surplus with china in 40 years. they must end unfair trade, take down barriers, and charge only reciprocal tariffs. the u.s. is losing $500 billion a year and has been losing bill i don't believe so of dollars for decades. cannot continue. garrett kenny picks up the rest of the story from washington. >> reporter: the big concern on wall street is the trade dispute escalates into a full-blown