(REUTERS) – Stock markets worldwide tumbled on Friday as falling Brent crude oil prices to seven-year lows and a drop in China’s yuan currency stoked investor risk aversion ahead of a widely anticipated U.S. interest rate increase next week.

All three major U.S. indexes sank over 1 percent as crude prices plunged on continued oversupply concerns. Indeed, the International Energy Agency said it sees the oil glut worsening in 2016 as demand slows and OPEC shows no signs of slowing production.

A fall in China’s yuan to its lowest in four-and-a half years on concerns over the slowing world No. 2 economy, and expectations of a U.S. rate hike, hurt shares worldwide. Concerns grew that weakness in the yuan could weigh on the global economy and on companies with strong export ties to China.

European shares slipped to their lowest in two months.

“We have the yuan at 4-1/2 year lows and that is causing unease in China and abroad. Last time the yuan fell like this, it caused a jolt for markets and anyone exporting out to China, like the auto makers and luxury brands, will feel the pain from a weaker yuan,” Jasper Lawler, market analyst at CMC, said.

In the spot market, the yuan CNY=CFXS hit 6.4564 against the U.S. dollar, its weakest level since July 2011.

Brent crude LCOc1 was down 3.45 percent at $38.36 a barrel after hitting $38.28, its lowest level since December 2008. U.S. crude CLc1 was down 2.18 percent at $35.96 per barrel after hitting $35.78, its lowest since February 2009.

MSCI’s all-country world equity index .MIWD00000PUS, which tracks shares in 45 nations, was down 1.23 percent, at 394.39.

The Dow Jones industrial average .DJI was down 1.1 percent, at 17,380.59. The S&P 500.SPX was down 1.06 percent, at 2,030.38. The Nasdaq Composite .IXIC was off 1.15 percent, at 4,987.34.

Europe’s broad FTSEurofirst 300 index .FTEU3 was down 1.86 percent at 1,401.52.

The dollar fell against the euro as concerns over weak commodity prices and the yuan’s slump overshadowed solid U.S. retail sales data. Those concerns were unsupportive of further monetary policy tightening by the Fed beyond December’s heavily anticipated rate increase.

“These external macro factors could limit the scope of Fed hikes next year and that is weighing on the dollar,” said Omer Esiner, chief market analyst at Commonwealth Foreign Exchange in Washington.

The dollar index .DXY, which tracks the greenback versus a basket of six currencies, was last down 0.33 percent, to 97.611.

U.S. Treasury debt prices surged as the drop in oil prices and weakness in stocks spurred investors to seek the relative safety of government bonds.

Benchmark 10-year U.S. Treasury notes US10YT=RR were last up 17/32 in price to yield 2.18 percent, from a yield of 2.24 percent late Thursday.

Gold prices bounced from earlier losses. Spot gold was up XAU= $3.07 at $1,074.21 an ounce.

(Additional reporting by Dion Rabouin and Gertrude Chavez-Dreyfuss in New York and Clara Denina and Sudip Kar-Gupta in London; Editing by Bernadette Baum)

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