US stock futures dropped in early Asian trade on Monday as rising coronavirus cases in the United States raised more doubts about a quick economic rebound from the massive downturn triggered by the pandemic.
US S&P 500 futures were down 0.4% at 2323 GMT, having fallen as much as 1.05% in earlier trade.
Chicago-traded futures indicate Japan's Nikkei is on course to fall 1.3%.
Apple Inc said on Friday it would temporarily shut 11 US stores as coronavirus cases continue to rise in southern and western states.
Data from Johns Hopkins University shows new US cases on Saturday hit the highest level since early May.
"The second wave is becoming a theme for markets. The increase in states such as Florida and South Carolina is big enough to be labelled as second wave," said Yoshinori Shigemi, global strategist at JPMorgan Asset Management.
"Whether there will be a lockdown may vary depending on region. It will be a tough decision for politicians. But they probably have no other choice if they are running out of hospital beds," he said.
The pandemic is accelerating globally with the World Health Organization (WHO) reporting a record increase in global coronavirus cases on Sunday.
Investors are also wary of developments in Hong Kong after details of a new security law for the territory showed Beijing will have overarching powers over its enforcement.
China's top legislative body, the National People's Congress Standing Committee, will meet on June 28, and the Global Times reported it would likely enact the Hong Kong security law by July 1.
In the currency market, the risk averse mood pushed the Australian dollar 0.2% lower to $0.6822 but other major currencies were mostly steady.
The euro traded at $1.1181, having hit a two-week low of $1.1169 on Friday.
The yen changed hands at 106.88 per dollar, not far from a one-month high of 106.58 to the dollar hit earlier this month.
Gold rose to $1,750 per ounce, near its May peak of $1,764.8, which was its highest since October 2012.