The Trump administration has also announced efforts to engage the World Trade Organization (WTO) in an effort to argue against unfair trade practices concerning Chinese state sponsored industries and technology licensing.
The four-day visit by Emmerson Mnangagwa, his first outside Africa since taking office, comes as Beijing is seeking to extend its economic and geostrategic foothold on the continent via the "Belt and Road Initiative", President Xi Jinping's signature trade and foreign policy plan.
There is a lot of rhetoric going back-and-forth about counter measures against the US, but it is hard to determine at this point how much of this is meaningful and realistic and how much is simply posturing.
"There's no doubt about it that exports are critical to our industry", he said.
With less than an hour to the close of United States markets, the Dow Jones Industrial Average was down 676 points. The benchmark index lost 1.2 percent in the first quarter of 2018 following nine straight quarters of gains.
Facebook stock also continued to fall Monday (2.75 percent) as the social network faces scrutiny over its sale and collection of user data.
The Toronto Stock Exchange's S&P/TSX Composite Index was down 67.96 points, or 0.44 per cent, to 15,299.33. Was letting China into the WTO a strategic mistake?
O'Rourke said the harvest this September and October and competition from rivals will determine how much the tariffs will sting for Washington's growers.
U.S. officials said the list of annual imports worth $50-$60 billion is likely to aim the "largely high technology" products and it could take more than two months before the tariffs come into play. "And that could be true for Mexico as well as for China".
On Monday, China responded to the duties on aluminum and steel U.S. President Donald Trump implemented by raising the import duties on U.S. fruit, pork and other products valued at more than $3 billion.
Among Oregon companies, ESI was down 8 percent, Intel was down 4.7 percent and Nike fell 4.2 percent. In addition to developing trade, they have also fostered greater military ties.
His new, unilateral trade steps, though, shocked many US businesses and foreign leaders, particularly because Trump had taken a more cautious approach in his first year, seeming to dial back some of the populist trade rhetoric he made during the 2016 campaign.
"The markets are getting a bit spooked by the prospects that this could just escalate downward, in more of a spiralling fashion, and each incremental announcement is followed by perhaps an even heavier hand in protectionist policy", said Fehr.
"It seems like the long arm of the government is interfering with investors' expectations", he said.
Trade agreements, now being renegotiated with Canada and Mexico are also uncertain.
Microsoft dropped 3 percent and Alphabet, Google's parent company, shed 2.4 percent.
"Everybody is bracing for that", Kleintop said of expected US tariffs on $50 billion to $60 billion a year of imports from China that will likely intensify U.S.
Health insurer Humana was one of the market's few winners following more reports Walmart could buy the company or create a new partnership with it. Humana is a major provider of Medicare Advantage coverage for people 65 and older.