* Euro zone data deals blow to recovery hopes * Brent crude hits three-week low * Euro hits 6-week low vs dollar, 3-week low vs yen By Angela Moon NEW YORK, Feb 21 (Reuters) - Global equity markets tumbled and the euro struck a six-week low against the dollar on Thursday after data that showed slow economic growth in both Europe and the United States. Oil prices also slumped, with Brent crude hitting a three-week low, after a euro zone business survey showed a decline that dealt a blow to hopes the region might soon emerge from recession. In the United States, the number of Americans filing new claims for unemployment benefits rose last week, while factory activity in the U.S. mid-Atlantic region unexpectedly contracted in February for the second month in a row. The weak data, however, failed to reverse sentiment that the Federal Reserve may tighten monetary policy sooner than markets had previously expected. "Everyone knows the Fed has to eventually withdraw their plan, and to investors today's data, which was generally weak, isn't enough to make a significant difference in the Fed's decision," said Jack De Gan, chief investment officer at Harbor Advisory in Portsmouth, New Hampshire. On Wednesday, minutes from the U.S. Federal Reserve's most recent meeting suggested the central bank may slow or stop buying bonds sooner than expected. U.S. stocks on Wednesday suffered their biggest one-day decline since Nov. 14. The Fed's quantitative easing measures, designed to stimulate the economy by expanding the Fed's balance sheet to buy bonds, has been credited with pushing money into the stock market. A withdrawal would remove a ballast for the markets. The MSCI world equity index was on course for its biggest daily loss of year. The index was off 1.3 percent on Thursday. The Dow Jones industrial average was down 52.00 points, or 0.37 percent, at 13,875.54. The Standard & Poor's 500 Index was down 6.86 points, or 0.45 percent, at 1,505.09. The Nasdaq Composite Index was down 16.93 points, or 0.53 percent, at 3,147.48. In other data, financial data firm Markit said its "flash," or preliminary, U.S. Manufacturing Purchasing Managers Index slowed to 55.2 this month from 55.8, which had been the best showing since April 2012. In Europe, shares closed sharply lower, stung by the weak economic data and by a steep fall on the Milan stock market on uncertainty over this weekend's Italian elections. Europe's Eurofirst 300 index shed 1.5 percent to close at 1,151.61. The blue chip Euro STOXX 50 index index fell 2.3 percent to 2,580,20, a new low for 2013.. The euro dropped to $1.3166, its lowest since Jan. 10, and well below a 15-month peak of $1.3711 reached on Feb. 1. The euro last traded at $1.3209, down 0.5 percent. The euro fell to a three-week low against the yen, pressured by the signs of economic weakness in Europe and the Italian elections, as well as expectations the Fed may start to reduce monetary stimulus earlier than had been thought. Against the yen, the euro fell to 122.23 yen, its weakest level since late January. It was last at 122.91, down 1.1 percent. "The PMI news is not good and shows the euro zone is under economic duress, and you add to the current uncertainty ahead of the Italian elections and we have a euro that is struggling to get ahead," said Matthew Lifson, senior trader and analyst at Cambridge Mercantile Group in Princeton, New Jersey. U.S. Treasuries rose on Thursday as worries over the lack of economic recovery in Europe, along with a struggling labor market and tepid business conditions in the U.S., prompted investors to buy assets perceived as safe havens. Benchmark 10-year Treasury notes were trading 12/32 higher in price to yield 1.97 percent, down from 2.01 percent late Wednesday but still well within the 1.93 percent to 2.06 percent range that has held sway for over three weeks. In other risky assets, oil fell to a three-week low below $114 a barrel on Thursday. The drop extended Brent crude's largest one-day slide in 2013 on Wednesday, alongside declines in other commodities and equities. Brent crude fell as low as $113.50, the lowest intra-day price since Jan. 29. U.S. crude slipped by $2.18 to $93.04.