By Richard Hubbard and Marc Jones
LONDON (Reuters) - World shares are on course for their worst weekly performance since June, depressed by Europe's debt troubles and the looming "fiscal cliff" that could slash U.S. public spending.
Even better-than-expected Chinese economic data for October, which pointed to a modest rebound in the world's second largest economy, failed to stem the declines on Friday.
The MSCI world equity index was down 0.3 percent at around 322.5 points by 1230 GMT. It has lost over two percent since Monday and looked set to close on Friday with a decline steeper than any other week since June.
"Concerns about the U.S. fiscal cliff and the situation in Europe have been prompting investors to take some risk off the table," said James Butterfill, global equity strategist at London private bank Coutts.
U.S. stock futures signalled a third day of falls for Wall Street when trading resumes. Data due out later includes the Thomson-Reuters University of Michigan sentiment survey where a small pickup to 83 from 82.6 is forecast.
In a further sign of nervousness, the dollar fell to its lowest in three weeks against the yen, which is often a refuge in times of stress. The greenback hit 79.21 yen, its lowest level since October 19 and down 0.3 percent on the day.
"You've only got to look at what's happening in the gold market, and with the equity markets falling quite heavily, that is playing back into strong demand for the yen," said Adam Myers, senior currency strategist at Credit Agricole CIB.
Gold hit a three-week high of $1,737.60 an ounce.
Prices for safe-haven U.S. Treasuries extended their gains for the week after the U.S. elections on Tuesday raised fears that Washington's politicians may struggle to find a compromise to cut the budget deficit before nearly $600 billion of spending cuts and tax increases kick in early in 2013.
Markets are also watching the U.S. debt ceiling, which needs to be raised to avoid a government shutdown.
The price increase in the benchmark U.S. Treasury 10-year note pushed the yield down 3 basis points to 1.59 percent.
In Europe falling industrial output in France, Italy and Sweden and a warning from a German ministry that the country's economy - Europe's largest - was expected to slow further in the fourth quarter and the first three months of next year, rattled investors.
The FTSE Eurofirst 300 index of top European shares was down 0.7 percent to 1090.20 as London's FTSE 100, Paris's CAC-40 and Frankfurt's DAX fell between 0.5 and 1.3 percent.
A worried German finance minister, Wolfgang Schaeuble, has asked a panel of economic advisers to look into reform proposals for France. Reported exclusively by Reuters, the unusual move reveals the depth of concern in Berlin at the weakness in the euro zone's second largest economy.
"Germany has benefited from the euro zone debt crisis in a way because a weaker euro helped its exports. But Germany appears to be starting to suffer from deterioration in the euro zone economy," said Mitsuru Saito, chief economist at Tokai Tokyo Securities in Tokyo.
A senior EU official also told Reuters it was unlikely ministers would reach agreement on Monday on whether to release Greece's next aid tranche and that another meeting would probably be needed.
"We still have the situation in Greece; the volatility indexes are showing that investors are not too worried at the moment - but that can change quickly so politicians need to act quickly," said Emile Cardon, a market economist at Rabobank.
German government bonds, favoured by risk-averse investors, rose; Bund futures added 23 basis points on the day to reach 143.20, adding to gains of more than a full point since last Friday's close.
The euro hit a two-month low against the dollar, down 0.3 percent at $1.2714, and was seen vulnerable to further losses.
"There has been a rather poisonous cocktail that is dragging the euro down, with weak European numbers today, renewed fears of the euro zone crisis with Greece back on the agenda," said Arne Lohmann Rasmussen, head of currency research at Danske Bank.
In industrial commodity markets the better news from top consumer China only partially offset the worries over the U.S. and European economies.
The Chinese numbers showed factory output and retail sales for October rising by more than expected, while inflation dipped to its slowest pace in nearly three years, giving policymakers scope to further loosen monetary policy.
That came right on cue for the start of the week-long leadership changeover in the ruling Communist Party.
U.S. crude oil prices down 50 cents to $85.43 a barrel. Brent futures were down 40 cents to just below $107 a barrel.
"Politics is going to take centre-stage as far as commodity markets are concerned," said Natalie Rampono, a commodity strategist at ANZ.
In Asian trading, Thursday's losses in global stocks weighed on Japan's Nikkei stock average which closed 0.9 percent lower.
MSCI's broadest index of Asia-Pacific shares outside Japan eased 0.2 percent on top of the previous day's 1.3 percent slide, its biggest one-day percentage drop in two months, leaving it 0.4 percent down on the week.
(Additional reporting by Atul Prakesh and Philip Baillie; Editing by Philippa Fletcher and Alastair Macdonald)