Global stocks pull back as wary investors monitor the spread of COVID-19 and unrest in Afghanistan

• Global stocks fell Tuesday on concerns of China regulation and the impact of COVID-19 on economic recovery.
• Investors are also monitoring the Afghanistan crisis, which has further dampened sentiment.
• Fed official Eric Rosengren said another strong jobs report could support a September taper announcement.

Global stocks traded lower on Tuesday as investors weighed the impact of the fast-spreading Delta variant, China's escalating regulatory crackdown, and the crisis in Afghanistan.

US stock futures linked to the Dow Jones and S&P 500 each fell 0.4%, suggesting a lower start to trading later in the day, after both indexes closed at record highs Monday. Nasdaq futures dipped 0.3%.

Excluding Apple, mega-cap tech stocks were among the biggest losers Monday, with the FANG+ index down almost 3% at one point. Tesla shares saw the biggest decline, falling nearly 5% after the US opened an investigation into the electric car-maker's autopilot system.

Weaker-than-expected Chinese economic data has contributed to the downbeat tone in markets, as has the persistent spread of the Delta coronavirus variant. Eight consecutive weeks of rising COVID-19 cases has raised the risk of a deterioration in economic outlook, Deutsche Bank strategists said.

The Taliban's takeover of Afghanistan has further dampened sentiment, reminding investors about medium to longer-term geopolitical risks, they said.

In his first address since Kabul's fall, President Biden said Monday he stood "squarely behind" the decision to withdraw US forces. He also laid out steps his administration is taking to quell the crisis.

Market consequences from the Afghan turmoil have been pretty limited so far, Deutsche strategists said. But they added such events have historically led to situations that have hit markets, such as the 9/11 attacks.

Boston Fed President Eric Rosengren added fuel to the debate over when the Federal Reserve will begin tapering late Monday, when he said that continued job gains could give the central bank reason to cut its monthly asset purchases.

"If we get another strong labor market report, I think that I would be supportive of announcing in September that we are ready to start the taper program," the Fed policymaker told CNBC.

Fed Chair Jerome Powell's appearance at a town hall with educators later Tuesday will be closely watched for more clues on monetary policy.

In Asia, China's State Administration for Market Regulation moved to tighten its control of the technology sector again. It issued draft regulations to ban unfair competition between internet companies and restrict their use of user data.

The regulations are seen as adding to compliance headaches for e-commerce marketplaces. Shares of Hong Kong-listed tech stocks slid after the rules were published, with Tencent and Alibaba dropping more than 4% each. Alibaba's US-listed shares fell 3%, and Tencent's lost 3.4%

The Shanghai Composite closed 2% lower Tuesday, while Hong Kong's Hang Seng fell 1.9%. Tokyo's Nikkei declined 0.3%.

In the UK, job vacancies topped 1 million for the first time on record in July, official figures showed. The unemployment rate slipped to 4.7% in the quarter to June. London's FTSE 100 lost 0.2% in the early going but has since reversed losses with a small gain.

Still, concerns over the global situation are rattling investors' nerves in Europe. The Euro Stoxx 50 shed 0.4%, and Frankfurt's DAX was 0.4% lower.

Oil prices extended losses after Reuters cited four OPEC+ sources who said they believe markets don't need more supply than planned, despite US pressure to increase output. Brent Crude fell 0.8% to $68.94 a barrel, and West Texas Intermediate declined 0.8% to $66.45 a barrel.

Gold gained 0.3% to $1,795 an ounce early Tuesday, despite the dollar strengthening to 92.70. The safe-haven metal should find plenty of buyers waiting on the dips, said Jeffrey Halley, a senior market analyst at Oanda.

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