China has vowed to step up COVID-19 testing and screening to prevent a rebound in cases.

But fears over a second wave of infections contributed to a fall in global stock markets on Thursday (May 14).

That and a dour assessment from the head of the U.S. Federal Reserve on Wednesday (May 13) dashed hopes for a quick economic recovery.

Jerome Powell warned of a recession worse than any since World War Two, and called for additional public spending.

That was seen as a pointed comment from a central banker who has avoided giving advice to elected officials.

Meanwhile, new outbreaks in South Korea and China are worrying investors, even as more countries begin to re-open their economies.

Every market in Asia fell, and MSCI's broadest index of Asia-Pacific shares outside Japan closed down 1.3 percent.

European shares also retreated.

The pan-European STOXX 600 slid over 1.5% in morning trade, falling past a one-week low hit on Wednesday.

Automakers, technology and banking stocks led declines.

Airbus slipped as much as 1.6% following reports that the aerospace group is exploring restructuring plans involving the possibility of "deep" job cuts.

London's FTSE 100 fell for a second straight day as investors worried that a recovery would be slower than expected.

In the U.S., the Trump Administration is pressing on with re-opening plans despite urgings of caution from medical experts.

A surprise drawdown of U.S. inventories helped oil prices make meager gains.

But the bleak outlook capped rises.

Brent crude firmed slightly to just over $29 per barrel and U.S. crude was up 1%.