NYSE workers
Traders work on the floor of the New York Stock Exchange (NYSE) on February 6, 2018 in New York City Spencer Platt/Getty Images

European stock indexes have opened lower after another tumble on Wall Street the day before caused jitters through global markets.

European markets had already fallen substantially on Thursday so their declines were not as deep as those seen elsewhere. Britain's FTSE 100 fell 0.4 percent Friday to 7,141 points, while Germany's DAX was flat at 12,262 and France's CAC 40 declined 0.3 percent to 5,136.

Asian markets also followed U.S. stocks down after the Dow, coming off a record high, entered a correction — or a 10 percent decline from its latest peak — for the first time in two years. The Shanghai Composite Index was off 4.1 percent after tumbling 5.5 percent at mid-morning. Tokyo's Nikkei 225 was off 2.3 percent and Hong Kong's Hang Seng retreated 3.2 percent.

Financial analysts regard corrections as a normal market event but say the unusually abrupt plunge might have been triggered by a combination of events that rattled investors. Those include worries about a potential rise in U.S. inflation or interest rates and whether budget disputes in Washington might lead to another government shutdown.