* Asian stock markets: https://tmsnrt.rs/2zpUAr4
* Yuan at new 11-1/2 yr low; offshore yuan weaken past 7.1 per USD
* Sterling jumps as traders cling to Merkel's backstop comments
* Traders await Fed chair Powell's Jackson Hole speech, G7 summit
By Tomo Uetake
TOKYO, Aug 23 (Reuters) - Asian shares struggled to make headway on Friday as uncertainty over how much further the U.S. Federal Reserve would cut interest rates added to investors' worries over slowing global growth.
With a trade war between the United States and China dragging on, and political tumult in Hong Kong, Italy and Britain adding to the tense backdrop, investors were keenly awaiting Fed Chair Jerome Powell's speech at a gathering of central bankers in Jackson Hole, Wyoming, later in the day (1400 GMT).
MSCI's broadest index of Asia-Pacific shares outside Japan .MIAPJ0000PUS edged 0.1% higher and was up 0.8% for the week, on track to break a four-week losing streak.
Japan's benchmark Nikkei .N225 added 0.3% and Australian stocks .AXJO rose 0.3%.
The Shanghai Composite .SSEC and the blue-chip CSI300 .CSI300 were up 0.5% and 0.7%, respectively, while Hong Kong's Hang Seng .HSI gained 0.5%.
Business surveys on Thursday suggested further slowing in advanced economies in August, but service sector activity remained resilient, offsetting some of the drag from weak manufacturing.
"It's going to be another wait-and-see day for traders ahead of Powell's Jackson Hole speech. Investors are hoping for some soothing words from him," said Hirokazu Kabeya, chief global strategist at Daiwa Securities.
Wall Street stocks were mixed on Thursday, with the S&P 500 .SPX closing little changed, while the Dow .DJI was up 0.2% and the Nasdaq .IXIC falling 0.4%. .N
In the U.S. bond market, the closely watched two-year, 10-year Treasury yield curve briefly moved back into inversion overnight, a shift that also occurred last week and sent financial markets into a tailspin amid worries of a sharp global downturn. inversion in the U.S. yield curve has presaged several past U.S. recessions, raising fears the decade-long expansion in the world's biggest economy might be nearing its end.
While markets overwhelmingly expect the Fed to follow up its first rate cut in a decade with more stimulus at its meeting next month, some policymakers disagree.
Kansas City Fed President Esther George, who dissented against the decision to ease in July, and Philadelphia Fed President Patrick Harker, who said he "reluctantly" supported the cut, both said the U.S. economy does not need more stimulus at this point. Fed President Robert Kaplan said the businesses had become much more cautious due to surprises on trade policy and he was "going to at least be open-minded about making some adjustment" if he sees continued weakness.
All of that has made Powell's speech in Jackson Hole pivotal for markets as they look for any clues on future easing, after the Fed last month cut rates for the first time since the financial crisis.
Any indications of hawkishness in the Fed chief's comments might hurt riskier assets, though the dollar stands to benefit.
The greenback slipped on Thursday, but moved within narrow ranges. In early Asian trading, the dollar was up 0.1% against a basket of major currencies to 98.293 .DXY .
The euro also was little changed against U.S. currency at $1.1073. A survey showing a surprise uptick in euro zone business growth for August was offset somewhat by trade war fears knocking future expectations to their weakest in over six years. pound GBP=D4 jumped to a three-week high of $1.2273 overnight after traders interpreted comments from German Chancellor Angela Merkel to mean that a solution to the Irish border problem could be found before Britain leaves the European Union on Oct. 31. on Wednesday challenged Britain to come up with alternatives to the Irish border backstop within 30 days, but French President Emmanuel Macron cautioned there would be no renegotiation of the Brexit deal. Sterling last quoted at $1.2234, 0.1% weaker on the day.
China's yuan extended losses, threatening to stoke trade tensions between Washington and Beijing.
Spot yuan CNY=CFXS slid to as low as 7.0992 per dollar, its weakest since March 2008, although the central bank set the midpoint rate at 7.0572, its weakest level in 11-1/2 years, but was much stronger than traders had expected. labelled China a currency manipulator early this month after a sharp slide in the yuan.
Concern about China's economy is growing because U.S. tariffs on roughly $150 billion of Chinese goods will take affect from Sept. 1. prices weakened overnight, with both Brent crude and U.S. West Texas Intermediate down 0.6% each, on worries about the global economy. O/R
Brent crude LCOc1 was last up 0.3% at $60.11 per barrel and WTI crude CLc1 added 0.2% to $55.46.
Gold prices dipped on Thursday but held near the pivotal level of $1,500 per ounce, underpinned by demand for the precious metal amid uncertainties around monetary policy, trade and geopolitical tensions. GOL Spot gold XAU= was last down 0.2% at $1,494.99 an ounce.