The recent bullish mood on equity markets quickly faded on Thursday as mixed messages from the Federal Reserve and a slowdown in China sparked a heavy sell-off on the FTSE 100, which lost more than two per cent of its value.Answering questions in Congress last night was Fed Chairman Ben Bernanke who seemed to U-turn on earlier comments by hinting that the central bank could begin to scale back quantitative easing "in the next few meetings" if there is a sustained improvement in the economy. Given that global central-bank stimulus has had a big part to play in the near-16% jump on the FTSE 100 since the start of 2013 (as of yesterday's close), there are concerns that a premature tapering could de-rail the economic recovery and see share prices begin to reverse.David White, a Financial Trader at Spreadex, said that Bernanke's comments came "like a cold splash of water to a piping hot rally"."The talk in the market right now is fear. Equities have come off their multi-year highs with a bang, being sent sharply lower by concerns that the market has, as it sometimes can do, got ahead of itself," he said.White added that despite the sell-off today, the FTSE 100 has still shown a "very healthy" year-to-date return. "Just how far the market pulls back over the next 24 hours will be critical for sentiment."However, tapering concerns were compounded today as better-than-expected economic data from the US - jobless claims came in lower than forecast while new-home sales beat estimates - threw more weight behind the argument to tighten monetary policy.Also weighing on sentiment was the news that factory activity growth in China moved backed into negative territory in May, with the manufacturing purchasing managers' index unexpectedly falling to a seven-month low of 49.6 from the previous 50.4.Global markets suffered steep declines on Thursday with Japan's Nikkei by far the worst hit, dropping 7.3% overnight. The plunge saw every constituent in Tokyo finish in negative territory, the first time that has happened since 2005.FTSE 100: Banks and miners fall early onA fall in risk appetite saw the banking and mining sectors drop sharply. Standard Chartered, Barclays, RBS and Lloyds were heavy fallers along with EVRAZ, Anglo American, Antofagasta and Glencore Xstrata.ARM Holdings was extending recent losses as Exane BNP Paribas joined the list of brokers to show caution on the chip designer stock following the group's investor day earlier this week. The broker downgraded its rating to 'neutral' today.Retail group Kingfisher was also under the weather after Nomura cut its recommendation to 'reduce', saying that the shares have gained too much recently "given weakness ahead".Drinks firm SABMiller was in the red despite increasing its full-year revenue from $31.4bn to $34.5bn in the year to end March.United Utilities was among the rare risers after delivering a increase in full-year profit on the back of a strong operational performance.FTSE 250: Salamander and Halfords provide a dragOil group Salamander Energy plunged after it issued a disappointing update on its Bedug-1 exploration well in the Bontang production sharing contract. Although the well was found to be a gas discovery, exploration was terminated as a result of high pressures.Car and bike parts retailer Halfords sunk after the firm slashed its full-year dividend by nearly a quarter as profits dropped in the year to March 29th. The company said its performance reflected a "demanding trading environment".St James's Place was also a heavy faller after Lloyds cut its stake in the wealth manager for the second time in three months, placing 77m ordinary shares (representing 15% of the company) at a 9.3% discount to last night's closing price.FTSE 100 - RisersTate & Lyle (TATE) 871.00p +1.63%British Sky Broadcasting Group (BSY) 791.50p +1.60%United Utilities Group (UU.) 787.50p +0.77%Fresnillo (FRES) 1,080.00p +0.37%Sainsbury (J) (SBRY) 382.30p +0.08%FTSE 100 - FallersAggreko (AGK) 1,758.00p -5.59%ARM Holdings (ARM) 995.00p -5.24%Anglo American (AAL) 1,570.00p -5.05%Standard Chartered (STAN) 1,539.00p -4.76%Antofagasta (ANTO) 958.00p -4.39%Hammerson (HMSO) 521.50p -4.31%Rio Tinto (RIO) 2,913.00p -4.26%Evraz (EVR) 148.90p -4.18%GKN (GKN) 299.20p -4.07%Glencore Xstrata (GLEN) 336.90p -4.02%FTSE 250 - RisersPayPoint (PAY) 914.50p +2.75%Brewin Dolphin Holdings (BRW) 211.80p +0.62%Kentz Corporation Ltd. (KENZ) 399.50p +0.50%BH Global Ltd. GBP Shares (BHGG) 1,245.00p +0.40%Telecom Plus (TEP) 1,250.00p +0.40%BTG (BTG) 339.50p +0.33%Balfour Beatty (BBY) 236.20p +0.17%F&C Commercial Property Trust Ltd. (FCPT) 107.90p +0.09%Booker Group (BOK) 129.80p +0.08%Workspace Group (WKP) 415.00p +0.07%FTSE 250 - FallersSalamander Energy (SMDR) 170.00p -17.07%Halfords Group (HFD) 333.30p -15.90%St James's Place (STJ) 573.00p -10.47%Ferrexpo (FXPO) 175.40p -8.79%FirstGroup (FGP) 134.60p -7.81%Euromoney Institutional Investor (ERM) 921.00p -6.97%New World Resources A Shares (NWR) 107.00p -6.96%Man Group (EMG) 124.90p -6.44%888 Holdings (888) 165.30p -5.38%Jupiter Fund Management (JUP) 345.00p -4.75%BC