Global stocks fall as euro-zone tensions escalate

US stocks fell on Wednesday as protests in Spain and Greece over euro zone austerity measures raised fresh concerns over Europe's ability to get its debt crisis under control.

The Dow Jones industrial average was down 44.04 points, or 0.33 percent, at 13,413.51. The Standard & Poor's 500 Index was down 8.27 points, or 0.57 percent, at 1,433.32. The Nasdaq Composite Index was down 24.03 points, or 0.77 percent, at 3,093.70.

Euro zone equities suffered their worst session in two months, as violent anti-austerity protests in Greece and Spain underscored the hurdles the bloc faces on its road out of recession and financial crisis.

The EuroSTOXX 50 index of euro zone blue chips fell 2.7 percent to 2,498.52 points, in its biggest one-day drop since early August. The fall was capped by technical support at the 23.6 percent Fibonacci retracement of the recent rally. The broader FTSEurofirst 300 closed down 1.9 percent to 1,100.98 points.

In Asia, Nikkei average fell 2 percent, breaking below the key 9,000 mark and hitting a two-week closing low, as a mass of companies went ex-dividend, while concerns over debt-laden Spain also dampened sentiment.

The Nikkei ended 184.84 points down to 8,906.70, breaking below its 25-day moving average at 8,983.84. The benchmark is down 1.1 percent this quarter, which ends this week. The broader Topix index lost 2 percent to 742.54.