By Hideyuki Sano

TOKYO (Reuters) - Asian stocks opened weaker and the British pound fell almost 2 percent in early Asian trade on Monday as markets struggled to shake off deep uncertainty sparked by Britain's decision to leave the European Union.

Global stock markets lost about $2 trillion in value on Friday, with MSCI's broadest gauge of the world's stock markets <.MIWD00000PUS> falling 4.8 percent, its biggest decline in nearly five years.

Among many questions the British exit, or Brexit, has triggered are just how much UK and European economies will slow, how they will negotiate their new relationship and how European leaders will try to boost the crumbling European Union.

"We believe that markets will remain cautious, as uncertainty over exit negotiations causes risk averse sentiment to linger," George Davis, chief technical analyst at RBC Dominion Securities in Toronto said in a note.

U.S. S&P mini futures <ESc1>, the world's most traded stock futures, fell 0.7 percent to 2,004 on Monday, edging near Friday's 3-1/2 month low of 1,999.

MSCI's broadest index of Asia-Pacific shares outside Japan <.MIAPJ0000PUS> dropped 0.5 percent, led by 1.2 percent fall in South Korean shares <.KS11> and a 1 percent fall in Australia <.AXJO>.

Japan's Nikkei <.N225>, however, rose 1.3 percent, a partial rebound after Friday's 7.9 percent fall.

"Given the huge trading volume on Friday, I suspect people have done at least the minimum amount of hedging they need to do," said a head of derivative trading at a Japanese brokerage firm.

"But we could see more selling in risk assets in the end. After all Brexit doesn't really support appetite for buying stocks."

The British pound fell 1.9 percent to $1.3433 <GBP=D4>, though it still kept some distance from the 31-year low of $1.3228 touched during Friday's wild trade.

Against the yen, sterling fell more than 2 percent to 136.85 yen <GBPJPY=>. That was more than 14 percent below its levels early on Friday when investors believed the "remain" camp would win the referendum.

The euro <EUR=> also came under further pressure, falling 0.8 percent against the dollar, as investors fret Brexit could stoke the anti-establishment mood in Europe.

"(There will be) sell-off in the euro as talk of other exit referenda builds," said Jerome Booth, chairman of New Sparta Asset Management in London. "This sell-off will be more profound and long-lasting and will be not just against the dollar and yen but also against the pound. It will also raise fears of significant loss of values for holders of Euro-zone government bonds."

The euro fell to $1.1031 compared to Friday's 3-1/2-month low of $1.0912.

Oil prices fell more than 1 percent in early trade, with international benchmark Brent futures <LCOc1> down 1.3 percent to $47.80 per barrel.

Demand for safe haven assets such as government debt and precious metals remained strong.

The 10-year U.S. debt yield dropped 8 basis points to 1.502 percent <US10YT=RR> in early Asian trade. On Friday, it fell as low as 1.40 percent, near its record low of 1.381 percent marked in July 2012.

U.S. interest rate futures have completely priced out chance of a rate hike by the Federal Reserve this year and pricing in less than 50 percent chance of a rate hike even by late 2017.

Gold rose more than one percent to $1,334.50 per ounce <XAU=>.

Still, in a sign Briton's shock decision to leave the European Union may be encouraging Europeans to seek the safety of the status quo, support for Spain's conservative People's Party (PP) surged in Sunday's general election.

(Editing by Lincoln Feast)