Tokyo's Nikkei briefly collapsed more than four percent, while US futures plunged with oil prices, safe haven gold hit a record high and the dollar retreated amid worries retaliatory measures will batter economies.

The panic came after the US president unveiled a blitz of harsher-than-expected levies aimed at countries he said had been "ripping off" the United States for years.

Against a backdrop of US flags, Trump said that "for decades, our country has been looted, pillaged, raped and plundered by nations near and far, both friend and foe alike".

The measures included a 34 percent tariff on rival China, 20 percent on key ally the European Union and 24 percent on Japan.

A number of others will face specifically tailored tariff levels, and for the rest, Trump said he would impose a "baseline" tariff of 10 percent. Auto tariffs of 25 percent meanwhile kicked in Thursday.

Investors are bracing for retaliatory measures, with governments making their anger clear.

China vowed "countermeasures" and urged Washington to cancel the tariffs, while calling for dialogue.

Japan said the move was "extremely regrettable" and could contravene World Trade Organization rules, while Taiwan described the levies as "highly unreasonable".

European Union chief Ursula von der Leyen called Trump's announcement a "major blow to the world economy" but vowed the bloc was "prepared to respond".

And France said Brussels was "ready for a trade war" and plans to target online services in response.

Thailand said it had a "strong plan" to handle the new US measures and hopes to negotiate a reduction, while Canadian Prime Minister Mark Carney warned "we are going to fight these tariffs with counter measures".

"We are going to protect our workers," Carney said.

- 'Shock and awe' -

Stephen Innes of SPI Asset Management said: "President Trump walked into the Rose Garden and detonated the most aggressive trade shock the market's seen in decades. This isn't a jab -- it's a full-on haymaker."

Wall Street "had talked itself into a softer, more symbolic move. Instead, Trump carpet-bombed the global supply chain".

"This was a 'shock and awe' tariffs campaign, dressed up in 'reciprocity' language but designed to throttle the trade deficit through brute force."

He said the measures meant inflation risks had surged and economic growth expectations would be cut, with the Federal Reserve "pinned between a hawkish rock and a deflationary hard place".

Tokyo pared its hefty drop but still ended down 2.8 percent, while Hong Kong, Sydney, Seoul, Manila, Mumbai, Shanghai and Singapore also fell. However, Wellington managed to eke out a small gain as New Zealand faced smaller tariffs.

London, Paris and Frankfurt all tumbled more than one percent, while Vietnam's stock exchange dived 7.8 percent after the country was hit with levies of almost 50 percent.

Wall Street futures were also battered, with the Dow dropping two percent, the Nasdaq plunging more than three percent and the S&P 500 off 2.8 percent off.

Safe havens rallied as traders sought to dump risk assets.

Gold hit a new peak of $3,167.84 and the Japanese yen strengthened to 147.04 per dollar from 150.50 the day before.

Among other currencies, the euro and pound both jumped more than one percent against the dollar on fears about the US economy and bets that the Fed will have to cut interest rates to deal with the impact on growth.

US Treasury yields hit five-month lows -- yields and prices go in opposite directions.

Oil also suffered big losses, with both main contracts down at least three percent on fears that the shock to economies would hit demand.

Among the big corporate losers, Japanese tech giant Sony shed 4.8 percent, while its South Korean rival Samsung was down 2 percent.

Car titan Toyota was off more than five percent, Nissan lost 3.7 percent and Honda was down 2.3 percent. Tokyo-listed tech investment firm SoftBank was off close to four percent.

Hong Kong-listed e-commerce giants fell after the removal of a duty-free exemption for small parcels from China. Alibaba and JD.com shed 5.0 and 5.2 percent respectively.

Tai Hui of JP Morgan Asset Management said the scale of the measures raised concerns about growth.

"US consumers may cut back on spending due to pricier imports, and businesses might delay capital expenditures amid uncertainty about the tariffs' full impact and potential retaliation from trade partners," he wrote in a note.

- Key figures around 0810 GMT -

Tokyo - Nikkei 225: DOWN 2.8 percent at 34,735.93 (close)

Hong Kong - Hang Seng Index: DOWN 1.5 percent at 22,849.81 (close)

Shanghai - Composite: DOWN 0.2 percent at 3,342.01 (close)

London - FTSE 100: DOWN 1.2 percent at 8,502.37

Dollar/yen: DOWN at 147.14 yen from 149.39 yen

Euro/dollar: UP at $1.0970 from $1.0814 on Wednesday

Pound/dollar: UP at $1.3137 from $1.2985

Euro/pound: UP at 83.51 pence from 83.33 pence

West Texas Intermediate: DOWN 3.2 percent at $69.44 per barrel

Brent North Sea Crude: DOWN 3.0 percent at $72.72 per barrel

New York - Dow: UP 0.6 percent at 42,225.32 (close)

dan/lb

Dow

S&P Global Ratings

Sony

Samsung Electronics

TOYOTA MOTOR

NISSAN MOTOR

HONDA MOTOR

SOFTBANK GROUP

Alibaba

JD.com

INDEX CORP.