Transcript for Treasury secretary: 'There is the potential of a trade war'

gring fears O a new trade the U.S. And China back and forth with threats of tarif on one not with American farmers, tech companies and manufacturers caught in middle. After the first round ofiffs from each side, president trump now threatening import taxes of $100 billion goodsf cha, and secretary mnuchin admitting a trade war could be real, and Americans could feel some pain. The Dow losing nearly 600 points. Jonathan Karl starts UF from the E house. Reporter: Atal day on wall stre stocks tumbling after prt trump escalahis threats toward China. Today, the president acledged his trade pol Y cause pain. I'm not saying there won't a little pain. But the market's gone up 40%, so we might lose a little bit of it, but W going Tave a much stron country when we're finished Reporter: Global markets have been btered since the president first announced plans to hit China with $50 billion in tariffs. If they charge us, we charge em the same ING. That's the way it's goto . Reporter: This week, China D back, threatening $5billion in tariffs on American pros, everything from soybeans to cars to airplanes. It couost thousaof American jobs.american farmers could be hit especially hard. As markets tumbled, the ident's netop economic advir set out to calm nves. We're not running a trade wa if you read this thing you'll E, this is just a proposed idea. Repor that reasd wall Street, but just hours later, president trump turned up th heat yetin, announng $100 billion in additional tariffs against China. Enter today, the treasury secretar-- TRE is the ntial of a trade war. And LE just be clear, it is not a trade war. The prident wants reciprocal trade. Reporter: So, now? Well, juast month president himself said the United States had been treated so badly for so long on trade that, quote, tra wars ared and easy to win. Does the president think that trade wars are easy to win? Is that sts view? I think the president feels like if he is in charge of those negotiatns, absolute. And Jon karlns us from the white house tonight, and Jon, the presiden top economic adviser calls the tariff just a proposed idea, but you're not hearing that kind language from the president himsf. Reporter: Well, Tom, it is true that tariffs have not gone into eff yet. The process could take a couple of months leaving time to negotiate, but the president sure seems dug inn this, and so dohe Chinese. As a Chinese government spokesman said todaare N afraid to fight a trade R. Tom? Karl starting us off tonight. Jon, thank you.

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