Asian, European and U.S. stocks fell hard Wednesday on rising fears and uncertainty about a possible Greek exit from the euro zone plus worries over slowing economic growth.

Traders said the rout stemmed from a global search for protection from whatever will happen if Greece leaves or is kicked out of the 17-nation currency union also hit U.S. stocks.

Uncertainty surrounding Greece's membership in the euro and possible contagion into other countries plagued by high deficits just isn't going away, at least not until Greek elections have taken place on June 17, Markus Huber, head of German sales trading at ETX Capital in London, told Bloomberg News.

Global equities, many of which had posted two days of gains this week, turned sharply lower.

Singapore's Straits Times closed 1.53 percent lower, Hong Kong's Hang Seng ended 1.33 percent down and Tokyo's Nikkei 225 settled 1.98 percent off. India's BSE Sensex index fell to its lowest level since January, partly as a result of the rupee's decline: It set a record low against the U.S. dollar.

European stocks closed down, as well. Germany's DAX index fell 2.3 percent, Britain's FTSE 100 dropped 2.5 percent and France's CAC 40 plunged 2.6 percent.

In afternoon trading, the Dow Jones Industrial Average, the Nasdaq Composite and the S&P 500 indexes were all down about 1.4 percent.

The World Bank cuts its forecast for Chinese economic growth this year to 8.2 percent, warning that a slowing Chinese economy could cut growth in emerging East Asian economies to two-year lows.

Meantime, Italian consumer confidence fell to a 15-year low and British retail sales fell last month at the fastest pace in more than two years.

In the U.S., the Congressional Budget Office warned that the U.S. economy could fall into a double-dip recession next year if Congress does not deal with the fiscal cliff, a phrase used to describe the expiration of tax breaks and automatic federal spending cuts that go into effect late this year -- unless Congress acts.

PC maker Dell Inc. (Nasdaq: DELL) plunged more than 12 percent in premarket trading after it issued a weaker-than-expected sales outlook.