New York (CNN Business) The Tariff Man, as President Donald Trump has called himself, set off another wave of selling on Wall Street, with the Dow tumbling below 25,000 to four-month lows on Friday.

Trump's threat to impose escalating tariffs on Mexico, one of America's largest and most important trading partners, amplified fears about slowing economic growth.

The Dow declined 355 points, or 1.4%, capping its sixth straight losing week. That's the longest slump since June 2011. It's also the first time the Dow has closed below 25,000 since late January.

"This is just the latest worry to put on the fire for investors," Ryan Detrick, senior market strategist at LPL Financial, wrote in a note to clients. "The big question at the end of the day though is can we really fight two trade wars at the same time?"

The Dow and S&P 500 declined nearly 7% apiece in May, their first losing months since December. The Nasdaq tumbled 8% on the month, its worst May since 2010.

Trump's vow on Thursday evening to impose tariffs on Mexico , one of America's largest trading partners, only exacerbate investor worries about how trade tensions will disrupt business and slow global economic growth. Wall Street was already growing concerned about the escalating trade battle with China.

The United States imported $346 billion of goods from Mexico last year, including everything from auto parts and avocados to beer and televisions.

Major corporations already found themselves caught in the crosshairs of the outburst of tensions with Mexico.

Levi Strauss LEVI Constellation Brands STZ tumbled 7%, reflecting concerns about the fact that up to a fifth of the company's jeans and clothes sold in the United States are manufactured in Mexico and China., which owns Corona and Modelo Especial, plunged nearly 6%.

'Alarming' decision

Trump said the United States will impose a 5% tariff on all Mexican imports starting on June 10 as a punishment for illegal immigrants crossing the Mexican border into the United States. The White House indicated the tariff would increase by increments of 5 percentage points each month until it reaches 25% in October.

Some analysts expressed concern that Trump is imposing tariffs in response to immigration problems, not economic or trade ones.

"Tariffs can be thrown around as an economic bomb for anything now," Peter Boockvar, chief investment officer at Bleakley Advisory Group, wrote in a note to clients. "Global growth rates will only continue to suffer."

Kristina Hooper, chief global market strategist at Invesco, called it an "alarming" decision by the US administration to open up a "new and unexpected frontier" by using tariffs as a "weapon" beyond just trade policy.

"Markets don't like surprises and this is a big surprise," Hooper wrote in a note.

Worse, there were signs that the crackdown on Mexico may not be part of a broader economic strategy on behalf of the Trump administration.

In fact, Robert Lighthizer, Trump's top trade official, joined Treasury Secretary Steven Mnuchin in opposing the tariffs on Mexico, sources told CNN.

Peso, Mexican stocks plunge

The tariffs on Mexico will be "highly disruptive," Goldman Sachs analyst Alec Phillips wrote in a note to investors Friday. The bank warned the new trade tensions could hurt the ability to enact a new North American trade deal to replace NAFTA.

Investors exited Mexican assets in response to the news.

Tariffs can be thrown around as an economic bomb for anything now." Peter Boockvar, chief investment officer at Bleakley Advisory Group

iShares MSCI Mexico ETF EWW Thetumbled almost 4%. The Mexican peso plunged 2.5% against the US dollar. That sharp currency move should help boost Mexican exports by making goods cheaper for overseas buyers.

Ford F Walmart WMT Many US companies — includingandrely on the country as a central part of their supply chains.

Mazda MZDAF Toyota TM Honda HMC Nissan NSANF The country is also a regional manufacturing hub for Japanese, South Korean and German automakers that assemble cars in Mexico and ship many of them to the United States. Shares inand plunged more than 7%, while losses forand Volkswagen reached 3% or more.

Investors flock to bonds, gold

Signs of worry abounded on Wall Street.

The CNN Business Fear & Greed Index of market sentiment ticked into "extreme fear" territory on Friday, compared with "greed" a month ago.

Cash poured into ultra-safe government bonds, driving the 10-year Treasury yield below 2.13% for the first time since September 2017. Just a month ago the 10-year yield was sitting at 2.5%.

Gold, which tends to rise when investors are scared, gained 1% and climbed above the $1,300 level.

VIX VIX Thevolatility index climbed 9%, though it remains well below the levels reached in December.

Halliburton HAL Occidental Petroleum OXY Hess HES US oil prices plunged 5.5% to a three-month low of $53.50 a barrel, reflecting fear about the economic impact of the tariffs on China and Mexico.andeach fell 3% or more. Crude tumbled 16% in May, snapping a four-month winning streak.

Global growth concerns

Beyond the trade front, investors were also unnerved by weak economic numbers overseas.

Activity in China's vast factory industry fell to a three-month low in May. New orders declined, likely reflecting pressure from the trade war.

In Germany, retail sales unexpectedly declined. That sent the German 10-year bond yield plunging deeper into negative territory to a record low.

"We don't want to lose the German consumer," Boockvar wrote. "The domestic side is what's kept their economy out of recession."

Longest weekly losing streak since 2011

The broadside against Mexico comes at a delicate time in global financial markets

US stocks have slumped and bond yields have plunged in part because of worries about the escalating trade war between the United States and China. Investors fear the tit-for-tat tariffs — and threats of non-tariff retaliation — will slow economic growth, dent consumer confidence and derail business investment.

"This latest round of tariffs will create economic uncertainty, and economic uncertainty creates wealth destruction," said Jack P. McIntyre, portfolio manager for global fixed income strategies at Legg Mason affiliate Brandywine Global.