U.S. stock markets posted slight losses Thursday after briefly making some gains.
The Dow Jones Industrial Average, S&P 500 and NASDAQ all fell less than half of one percent.
European markets were down sharply. Key indexes were off as much as 2.4 percent in early trading, but losses eased to about one percent by the close of trading.
The stock market troubles began earlier this week on concerns about the health of Chinese markets and the U.S. economy.
The Shanghai index lost nearly three percent on Thursday. An even more drastic drop in Shanghai shares earlier this week sparked the current market sell-off.
Shares in Hong Kong dropped 1 1/2 percent, while Japan's market closed about nine-tenths of a percent lower.
Smaller markets in New Zealand and the Philippines rebounded.