President Donald Trump's latest threat to launch a trade war with Mexico sent markets tumbling on Friday -- and some American investors and manufacturers are sounding the alarm about what it means for the U.S. economy.

Politico reports that corporate America is feeling "unnerved" by Trump's surprise threat against America's second-largest trading partner, and they are particularly dismayed that it's coming at a time when the president's trade talks with China have completely stalled.

"This is a colossal blunder," David Kotok, chief investment officer at Cumberland Advisors, told Politico.

Kotok singled out top Trump trade adviser Peter Navarro for giving the president "wrongheaded" advice that is "sinking" his administration.

National Association of Manufacturers President and CEO Jay Timmons described Trump's latest actions against Mexico "a Molotov cocktail of policy" that would be hard on manufacturers and their employees, whose fortunes the president made a centerpiece of his 2016 campaign.

And Megan Greene, global chief economist at investment firm Manulife, told the publication that she can't imagine the Trump administration has the capacity to manage two trade wars at the same time.

"A two-front trade war is clearly negative for growth, and I don’t know how our trade officials even have the bandwidth to deal with it," she said.

Read the whole report here.