LONDON (AFP) - Global stock markets staged spectacular gains Monday as governments pumped billions of dollars into banks crippled by the credit crunch, coaxing newly confident investors into buying shares. Wall Street skyrocketed at the opening, with the Dow Jones Industrial Average 6.19 percent in positive territory at 8,974.56 by mid-day. The tech-heavy Nasdaq had surged 6.09 percent to 1,749.93. Most European markets closed with double-digit increases. Hong Kong surged 10 percent in earlier Asian trade. The London FTSE 100 index of leading shares jumped 8.26 percent to close at 4,256.90 while in Paris the CAC 40 rose 11.18 percent " its largest ever one-day gain " to 3,531.50. The Frankfurt Dax soared 11.40 percent to 5,062.45. There were gains of 11.39 percent on the Swiss Market Index, 11.49 percent in Milan and 10.65 percent in Madrid. Bucking the trend was Moscow, where Russia's two stock exchanges closed down more than four percent. The sharp falls came despite a Kremlin announcement that President Dmitry Medvedev had signed off on a rescue plan that is to provide an estimated 150 billion dollars to prop up Russia's troubled financial markets. Stock markets in the Middle East meanwhile made a strong comeback led by bourses in the oil-rich Gulf. The Saudi market, the largest in the Arab world, closed up 9.5 percent well above the 6,000-point mark after plunging to a four-year low of 5,794.87 at the start of the trading week on Saturday. "We have had our first significant bounce in the markets for sometime now," City Index market strategist Joshua Raymond said in London. But he cautioned: "It's a dangerous time to start believing we have hit a bottom in the markets. With the volatility here to stay and confidence likely to seesaw for sometime, we are only really going to be able to tell if we have hit a bottom a month after we have done so." Investor sentiment got a boost after the leaders of the 15-country eurozone, following the lead of Europe's financial giant Britain, agreed over the weekend on a high-stakes joint bid to pull the world financial system back from the brink of collapse. "The main message from the weekend meetings is that governments the world over seem to get the severity of the financial crisis now and are intent on taking extreme measures to improve matters," said Patrick O'Hare, analyst at Briefing.com. In a sign that banks are at last willing to lend to one another and to businesses, two key interbank lending rates, Libor and Euribor, eased sharply Monday on stepped-up European moves to boost guarantees to struggling banks. The three-month London inter-bank offered rate (Libor) in dollars fell to 4.7525 percent from 4.8187 percent on Friday. Germany, France, Spain, and Austria Monday pledged a total of 1.4 trillion dollars Monday, with the other 11 members of the eurozone single currency bloc set to follow suit ahead of a EU summit on Wednesday. The lion's share of the funds will be used to guarantee interbank loans, which all but dried up in the panicked month since the fall of US bank Lehman Brothers, threatening the supply of credit to the wider economy. In Germany, Chancellor Angela Merkel's cabinet approved an 80-billion-euro package to buy bank stocks and 400 billion euros in interbank loan guarantees. French President Nicolas Sarkozy rolled out a 40-billion-euro lifeline to recapitalise the country's banks, and 320 billion euros to underwrite loans. "Nothing will be spared to prevent the crisis getting any worse," Sarkozy told journalists. "The greatest danger is not to take risks, it is to do nothing." Britain said it would invest up to 37 billion pounds in ailing British banks Royal Bank of Scotland, HBOS and Lloyds TSB. Central banks in Europe also fired a new broadside on Monday to free up frozen lending, by providing commercial banks with unlimited amounts of dollars in a joint operation that might be reinforced by their key Japanese ally. But amid the euphoria analyst Ben May at Capital Economics warned that "while the latest coordinated actions are a welcome sign that the region's policymakers are trying to tackle the banking crisis, we still expect a tightening in credit conditions in 2009 to prompt GDP growth (in the eurozone) to slow from around 1.0 percent this year to about zero in 2009." Meanwhile, the United States said it was ready to buy equity in a broad array of financial institutions as part of the 700-billion-dollar bail-out for the banking sector that was agreed 10 days ago. Wall Street was also lifted by news that Mitsubishi UFJ Financial Group, Japan's largest financial group, agreed a 9.0-billion-dollar investment in Morgan Stanley in a vital boost to confidence in the ailing bank.