US stocks mixed as retail sales data shows spending slowed more than expected in July

• US stocks dropped Tuesday on a larger-than-expected drop in retail sales in July.
• Investors also mulled how conflict in Afghanistan will impact the economic recovery.
• The Fed's Powell will host a town hall with educators and students today at 1:30 pm ET.

US stocks were mixed on Tuesday after spending at retailers and restaurants fell more than expected in July and concerns mounted over the pace of the economic recovery.

Retail sales fell 1.1% to $617.7 billion last month, the Census Bureau announced Tuesday morning. Economists surveyed by Bloomberg expected sales to fall 0.2% to roughly $620 billion.

Investors are also adding the Afghanistan crisis to a growing list of factors that could impact stock returns, said Nigel Green, chief executive and founder of deVere Group. The fallout from the delta variant of COVID-19, concerns about peak earnings, disappointing Chinese economic data, and how this week's Fed minutes will impact policy are among the other concerns.

"There will be questions regarding stability in the Middle East, the global influence of the U.S. and the mounting pressure on Biden, the prospect of increasing international terror threats, and the growing dominance of China's renminbi," Green said.

Federal Reserve Chairman Jerome Powell will host a town hall with educators and students today at 1:30 pm ET. Traders will be listening for the Fed chair to drop any hints about changes to economic policy.

Here's where US indexes stood at the 9:30 a.m. ET open on tk:

• S&P 500: 4,479.71, up 0.26%
• Dow Jones industrial average: 35,625.40, up 0.31% (110 points)
• Nasdaq composite: 14,793.76, down 0.93%

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.

West Texas Intermediate crude slipped 0.37% to $67.05 per barrel. Brent crude, oil's international benchmark, slid 0.1%, to $69 per barrel.

Gold was flat at $1791 per ounce.