* World stocks hit highest in 2 1/2 weeks
* U.S. Treasury yields decline after Powell comments
* Euro zone bond yields fall
* Investors remain cautious on trade before Trump-Xi G20 meeting
* Graphic: World FX rates in 2018 tmsnrt.rs/2egbfVh
By Helen Reid
LONDON, Nov 29 (Reuters) - A more dovish tone from Fed Chairman Jerome Powell helped to revive risk appetite on Thursday, driving world stocks to their highest in more than two weeks, as European equities joined a global rally and core bond yields fell.
European stocks rallied, with the leading euro zone index up 0.8 percent, and tech, mining and autos sectors - the worst hit by recent losses - scoring the biggest gains.
Yields on German bonds fell, tracking a decline in U.S. Treasury yields, after Powell said on Wednesday that U.S. interest rates were "just below" neutral, less than two months after saying rates were probably "a long way" from that point.
"Given the volatility you've seen recently, it's probably quite reasonable to expect a little bit of a bounce. That being said, given the headwinds out there I can't see it being sustained," said Gary Waite, portfolio manager at Walker Crips in London.
Powell's comments triggered a rally in U.S. stocks and pushed the U.S. Treasury 10-year bond yield as low as 3.01 percent on Thursday, its lowest level since mid-September and down from this month's high of 3.25 percent.
The yield on two-year Treasury bonds fell for the third straight session.
The dollar, which has outperformed bonds and the S&P 500 this year thanks to rising yields and trade tariffs, fell back on Powell's comments. The dollar index inched down to 96.731 following an overnight loss of 0.6 percent.
In Europe, Italy's government bond yields also dipped ahead of an auction of five- and 10-year bonds. Demand is expected to much stronger than at last week's BTP Italia deal targeting retail investors.
Italy's five-year bond yield dipped 4 bps to 2.36 percent and the closely-watched spread over Germany was at 294 bps.
Italian debt has rallied this week as the government said it was ready to compromise with the European Union on its budget deficit target.
European stock gains came on the heels of a broadly positive session in Asia.
MSCI's broadest index of Asia-Pacific shares outside Japan rose 0.6 percent, although the Shanghai Composite Index slipped 1 percent.
Gains were tempered by investor jitters before trade talks between U.S. President Donald Trump and Chinese President Xi Jinping on Saturday, during the G20 summit in Argentina.
Analysts saw a chance of a knee-jerk rally in markets on any signs of progress, though substantive concessions would be needed for a more sustained recovery.
"Trade détente at the G20 is unlikely but it’s not priced. Even with EM recouping relative performance since early October, a pretty severe trade downturn still looks priced in," said Citi analysts.
Key to markets will be whether Xi can persuade Trump to postpone a sharp tariff hike on Chinese goods due to take effect Jan. 1.
In currencies, the euro edged 0.04 percent higher at $1.1370 after advancing 0.7 percent the previous day.
Sterling lost 0.4 percent to $1.2771 against the dollar after Bank of England Governor Mark Carney warned a disorderly Brexit could trigger a worse economic downturn for the UK than the financial crisis.
In commodities, oil prices regained some ground from losses in the previous session, but an increase in U.S. crude inventories and uncertainty in the run to an OPEC meeting next week kept markets under pressure.
U.S. crude futures were up 0.3 percent at $50.41 per barrel after sliding 2.5 percent the previous day.
Brent crude LCOc1> rose 0.2 percent to $59.69 per barrel. It has slumped 21 percent this month, during which it fell to a 13-month trough of $58.41.
Emerging market stocks hit a three-week high, with the index up 0.7 percent as investors bought back into risky assets.
Reporting by Helen Reid, additional reporting by Abhinav Ramnarayan; editing by Larry King