Donald Trump's threats to slap steep tariffs on Chinese and Mexican imports may have won him votes in Republican primaries but they would likely backfire, severely disrupting U.S. manufacturers that increasingly depend on global supply chains.

The Republican presidential front-runner's campaign pledges to impose 45 percent tariffs on all imports from China and 35 percent on many goods from Mexico would spark financial market turmoil and possibly even a recession, former trade negotiators, trade lawyers, economists and business executives told Reuters.

"I don't mind trade wars when we're losing $58 billion a year," Trump said in a Feb. 25 debate, referring to the 2015 U.S. goods trade deficit with Mexico. Economists dispute the idea the United States is "losing" money as the trade deficit is simply the difference between what the United States imports and what it exports to a country.

"Imposing tariffs or putting up trade barriers may sound good, but it will hurt our economy and credibility," said Wendy Cutler, the former acting deputy U.S. Trade Representative who helped lead U.S. negotiations in the 12-nation Trans-Pacific
Partnership trade deal last year.

Among those hardest hit would be the U.S. auto industry, which has fully integrated Mexico into its production network. Some $118 billion worth of vehicles and parts flowed north and south across the border tariff-free last year, according to U.S. Commerce Department data.

A 35 percent tariff would raise costs for Ford Motor Co's U.S.-assembled F-series and medium-duty pickup trucks that use Mexican-made diesel engines, one of its most profitable vehicle lines.

Ford CEO Mark Fields on Wednesday defended the company's investment strategy, which includes $9 billion for U.S. plants over the next four years, saying, "We will do what makes sense for the business."

Buyers of Fiat Chrysler Automobiles NV's popular Ram 1500 pickup trucks assembled in Saltillo, Mexico, could see their $26,000 base price pushed up by $9,000 if the tariff is fully passed on to consumers. A Chrysler spokesman declined to comment on Trump's statements.

Trump's campaign said in a statement that U.S. trade policy constitutes "unilateral economic surrender" and needs complete change because it allows foreign competitors to shut out U.S imports, devalue their currencies and unfairly target U.S. industries.

"I don't think he does our issue any favors by making it so incredibly jingoistic and bombastic," said Scott Paul, president of the Alliance for American Manufacturing, a group that allies domestic steelmakers and other manufacturers with the United Steelworkers union.