Japan's Nikkei stock index plunged more than six percent Friday, while European stocks also declined. Japan's key stock index is now down more than 20 percent from its recent peak.
Investors said they are concerned by a World Bank report that reduced the expected growth rate for China's economy. They appear even more worried that central banks will cut back efforts to stimulate the economy. Those efforts currently include the U.S. Federal reserve setting interest rates at historic lows and a program of purchasing $85 billion a month worth of securities.
Top Fed officials are scheduled to meet next week in Washington to assess the economy and discuss interest rates and other policies. Most economists expect they will keep interest rates steady. The head of the Federal Reserve, Ben Bernanke, has said the Fed will continue efforts to stimulate the economy until there are further improvements in the unemployment situation.