Markets went into free fall Wednesday and the Mexican peso tanked as Donald Trump appeared to be moving into the lead in the race for the White House.

European stocks tumbled in opening deals on Wednesday after Donald Trump was elected US president, beating market favourite Hillary Clinton and sparking investor fears over the world economy.

In initial deals, London's benchmark FTSE 100 index shed 1.87 percent to 6,718.85 points, Frankfurt's DAX 30 dived 2.9 percent to 10,181.89 points and the Paris CAC 40 index slid 2.8 percent to 4,350.07 compared with Tuesday's close.

Safe haven assets rallied as investors went running for cover, with the yen and gold rushing higher.

Tokyo ended the morning session 2.2 percent down, having been up more than one percent at one point, while Hong fell 2.1 percent and Shanghai sank one percent.

Sydney gave up 1.7 percent, Seoul shed 1.7 percent and Singapore dived 1.4 percent. There were also losses of more than one percent for Taipei and Jakarta.

Futures on the Dow on Wall Street plunged 2.6 percent.

Tomoichiro Kubota, a senior analyst at Matsui Securities in Tokyo, said: "Overall, the market has priced in a Hillary victory by about 80 to 90 percent. If Trump wins, we can't deny the possibility of wild moves."

The Mexican peso -- which was battered by Trump's anti-immigrant rhetoric earlier in the campaign -- tumbled towards record lows against the dollar.

The greenback at one point hit 19.8619 pesos up almost 10 percent from its earlier low and close to its record of 19.93 pesos.

The peso is considered a proxy of Trump's chances because of his anti-Mexican rhetoric -- including his pledge to remove undocumented immigrants, build a border wall and tear up a trade deal.

However the dollar tumbled against the yen as investors rushed into the Japanese unit, which is considered a safe bet in times of uncertainty and turmoil. The greenback was at 102.40 yen, down from above 105 Tuesday.

The euro also rose one percent against the dollar, while gold soared 5 percent to $1,331.

Oil prices plunged, with WTI sinking 3.3 percent and Brent 2.8 percent lower.

- Key figures around 0230 GMT -

Tokyo - Nikkei 225: DOWN 6 percent at 16,153.40

Hong Kong - Hang Seng: DOWN 2.1 percent at 22,427.87

Shanghai - Composite: DOWN 1.0 percent at 3,115.74

Dollar/Mexican peso: UP at 19.8078 from 18.6152 pesos late Tuesday

Pound/dollar: UP at $1.2406 from $1.2378 Tuesday

Euro/pound: DOWN at 89.30 pence from 89.03 pence

Euro/dollar: UP at $1.1150 from $1.1020

Dollar/yen: DOWN at 102.40 yen from 105.14 yen

Oil - West Texas Intermediate: DOWN $1.50 at $43.48 per barrel

Oil - Brent North Sea: DOWN $1.29 at $44.75 per barrel

New York - Dow: UP 0.4 percent at 18,332.43 (close)

London - FTSE 100: UP 0.5 percent at 6,843.13 (close)

Republican Trump defeated his Democratic rival to become the 45th president of the United States, sending shockwaves across global world stock markets.

"This is another black swan for European stocks -- despite Brexit, markets were still not prepared for a Trump win and stocks will bear the biggest brunt for it," City Index analyst Ken Odeluga told AFP.

"It is a long-term negative for global growth because of the protectionist instincts of President Donald Trump.

"Global trade will be curbed and the biggest multinationals face challenges to revenue growth as the expansion of globalisation itself comes into question."