Markets soared and world leaders praised a landmark deal aimed at stemming the eurozone debt crisis on Thursday, as questions about the details of the plan were swept aside by a wave of relief. President Barack Obama led international praise for the deal -- reached after marathon EU talks in Brussels -- welcoming what he called \"important decisions\" that would \"lay a critical foundation for a comprehensive solution to the eurozone crisis.\" With nothing less than the future of the eurozone and the health of the global economy at stake, investors also cheered the end of months of uncertainty and perceived prevarication. Stock markets from North American to Europe to Asia soared in tandem with oil prices and the euro, as massive relief rally took hold. The main stockmarket indices in the West rose from between 2.8 percent to more than 6.0 percent on the news. But Obama\'s comments, after months of pressing the European Union to protect the euro and prevent the crisis dragging the world back into recession, were tinged with a sense of a job not yet finished. \"We look forward to the full development and rapid implementation of their plan. We will continue to support the EU and our European allies in their efforts to address this crisis as we work together to sustain the global recovery and put our people back to work.\" The broad agreement was designed to address the continent\'s three-pronged crisis: avoiding a Greek default, backstopping other countries struggling with debt and improving the war chests of at-risk banks.  German Chancellor Angela Merkel and French President Nicolas Sarkozy were keen to herald the agreement, which resuscitated the idea that a Franco-German motor can still drive Europe when needed. \"We have done what needed doing,\" said German Chancellor Angela Merkel. Sarkozy said the agreement had saved Europe and the whole world from disaster. \"We had to face up to all this ... If there had not been an agreement last night, it was not just Europe that would have sunk into catastrophe, it was the whole world,\" he said in a televised interview. In Athens, Prime Minister George Papandreou said Greece, the epicenter of the crisis, had won a battle \"of huge importance for the country\" which would now aim to become productive once again. But the deal left some key questions unanswered about the long-term coherence of the eurozone -- particularly how budget discipline could be maintained in the future across the 17 countries of the disparate monetary union. It also remained to be seen whether bank writedowns of 50% on Greek debt would trigger a wave of insurance claims, spreading damage through the financial system. Some commentators doubted whether the deal will deliver growth, the key to ultimately getting past the region\'s debt problems. \"The plans... look more like a peashooter than the \'bazooka\' previously promised to tackle the region\'s problems,\" skeptical Capital Economics analysts told clients. \"We have not altered our view that the crisis will deepen over the coming quarters, ultimately resulting in some form of break-up of the currency union.\" EU leaders, often accused of doing too little too late, finally clinched the grand plan to tame the debt crisis early Thursday after 10 hours of talks. With the global economy stalling, Europe had come under intense pressure to put its house in order to save Italy and Spain from following Greece, Ireland and Portugal into needing huge bailouts from the EU and International Monetary Fund. The plan includes quadrupling the firepower of the European Financial Stability Facility, the EU emergency rescue fund, to one trillion euros; a new 100 billion euro bailout for Greece; a deal forcing banks to take a 50 percent loss on their holdings of Greek debt, to lessen Athens\' financing burden; and a push for banks to strengthen their capital base by a collective 100 billion euros. \"The European fix is in,\" said Patrick O\'Hare of Briefing.com. Investors \"appear to be pleased with what they have heard, even though it isn\'t exactly a plan where all the i\'s have been dotted and the t\'s have been crossed,\" O\'Hare said. Emerging economic giants China and Russia vowed to support the expanded rescue fund directly. But Beijing was not afraid to issue a note of warning too. \"Emerging economies should not be seen as the EU\'s good Samaritans -- in the end the EU has to pull itself out of the crisis,\" said China\'s official Xinhua news agency. In Frankfurt, banks poised to take a 50 percent \"haircut\" loss on their Greek debt issued a similar message. \"EU leaders have proven they can act,\" said the powerful German banking federation BdB. \"It is now up to the politicians to keep the pressure on Greece and other troubled eurozone countries to reform.\"  The banks\' debt writedown proved perhaps the toughest nut in the talks Wednesday night and early Thursday morning. In signs of backroom drama, Sarkozy and Merkel broke off from the summit talks to personally cut the deal with the head of the banking lobby IIF, Charles Dallara. \"We said it was our last word, our last offer,\" said Merkel of threats to allow Greece to default if the banks failed to accept the terms offered.