The BSE benchmark Sensex which plunged by 467 points in early trade today, lost more of its ground and was trading 564 points in the negative territory at 17,129 when reports last came in.The 30-share Sensex, which had lost nearly 620 points in the previous three straight sessions, tanked another 467 points to trade at 17,226 points in the first few minutes of trade.In a similar fashion, the wide-based National Stock Exchange Nifty index was trading 165 points in red at 5,167 points.In the Asian region, Hong Kong's Hang Seng Index was down 4.81 per cent, while Japan's Nikkei lost 3.36 per cent. The Dow Jones Industrial Average in the US ended 4.31 per cent lower yesterday, its worst one-day drop since December 2008.Meanwhile, Asian stock markets have slumped; extending a global equity sell-off after Wall Street had its worst day for almost three years. Japan's main Nikkei 225 index shed 3.4 per cent to 9,329.75. South Korea lost 4.2 per cent while Australia slid 2.4 per cent.Also in New York, the S&P 500 index fell 4.8 per cent and the tech-rich Nasdaq was more than 5 per cent lower.Frankfurt's Dax and London's FTSE 100 indexes had their worst day this year closing almost 3.5 per cent lower as investors fretted that Italy and Spain might become engulfed in the debt crisis. Investors sought the relative safety of gold sending the price of the metal to a new record high of 1677 dollars an ounce.In Europe, Lloyds Banking Group fell 9.9 per cent and Royal Bank of Scotland was down 7 per cent. France's Societe Generale lost 6.9 per cent and Germany's Commerz bank dropped 6.8 per cent in Frankfurt.