Asian shares and U.S. stock futures fell on Wednesday as concern about a resurgence of coronavirus cases in some countries cast doubt on the strength of global growth and demand for crude oil.

MSCI's broadest index of Asia-Pacific shares outside Japan (.MIAPJ0000PUS) fell 0.6%. Australian stocks (.AXJO) dropped 1.25% and shares in China (.CSI300) were down 0.46%.

Stocks in Tokyo (.N225) slumped by 1.79% due the growing likelihood that Tokyo, Osaka and surrounding areas will be put on lockdown due to a new wave of coronavirus infections.

S&P 500 e-mini stock futures also fell 0.18%.

Crude futures extended declines from a one-month high in Asian trading on speculation that coronavirus restrictions in India, the world's third-largest oil importer, will hurt energy demand. read more

Recent optimism about rising vaccination rates in the United States, Britain, and Europe is shifting to concern that record coronavirus infections in India and the reinforcement of travel restrictions will act as a brake on the global economy.

"Renewed concerns about the global economic recovery weighed on commodity prices and commodity currencies. Many countries around the world, such as India and Brazil, set new records for infections and deaths," analysts at Commonwealth Bank of Australia said in a research note.

"As long as the virus persists, there is a risk virus mutants develop and spread to other countries."

Declines in Asian shares followed a downbeat day on Wall Street. The Dow Jones Industrial Average (.DJI) fell 0.75%, the S&P 500 (.SPX) lost 0.68%, and the Nasdaq Composite (.IXIC) fell 0.92% on Tuesday as investors sold airlines and travel-related shares due to fear of a delayed recovery in global tourism.

Some tech shares and companies that benefited from stay-at-home demand could face further pressure after Netflix Inc (NFLX.O) reported disappointing subscriber growth for its movie streaming service, which sent its shares down 11% in after-hours trading. read more

U.S. crude dipped 0.4% to $62.42 a barrel, while Brent crude fell 0.26% to $66.40 per barrel.

India, the world's second most populous country and a major energy consumer, reported its worst daily death toll on Tuesday, with large parts of the country now under lockdown.

The Canadian dollar , the Mexican peso , and the Norwegian crown steadied during Asian trading after falling on Tuesday, but analysts say more declines the currencies of major oil exporters are likely if energy prices continue to fall.

The dollar index against a basket of six major currencies traded near a seven-week low, hurt by a dip in U.S. Treasury yields as some investors sought the safety of holding government debt.

Investors are closely watching an auction of 20-year Treasuries later on Wednesday, which will be an important gauge of global demand for fixed income.

Ahead of the auction results, the yield on benchmark 10-year Treasury notes traded at 1.5660%, near a six-week low. Yields on 20-year Treasuries stood at 2.1531%, close to a seven-week low.

In a sign of growing risk aversion, spot gold traded at $1,778.18 per ounce, close to a seven-week high reached on Monday.