Just as America's recession begins to ebb, trouble is brewing in Europe that may prolong a downturn on the Continent and ricochet through the global economy as it struggles toward a recovery. A rout in stock markets that began in Europe spread to Wall Street on Thursday, amid fears that Europe may be the world's next financial flashpoint. Pressure has been mounting across the Atlantic as Greece, Portugal, and a handful of struggling countries that use the euro scramble to pay off mountains of debt accumulated from years of profligate spending. The Dow Jones Industrial Average slid 2.6 percent to 10,002.18, after briefly falling below 10,000 for the first time since November, as American investors grew more uncertain about the future of Europe's economy. Stock markets across Europe slumped as much as 6 percent, and worries that the quandary might push even big European nations like Spain into a financial crush drove the euro to $1.37, a seven-month low against the dollar. Like America, Europe has been slow to exit a recession. France, Germany and the Netherlands -- the biggest of 16 countries that use the euro as their currency -- have tried to put their financial houses back in order quickly. But countries on the fringe, including Greece, Portugal, Spain and Ireland, are having trouble paying for years of debt-driven expansion. They could default on their debts, sending investors fleeing and prolonging the economic downturn. The pressure on these countries to discipline their finances has raised questions about whether the currency union that has peacefully bound Europe's economies for more than a decade risks unraveling. Fearful investors have started asking whether France, Germany and other rich countries should be forced to bail out their poorer cousins, or simply allow them to default -- an outcome that would have repercussions for Europe and financial markets worldwide. The current troubles began in Greece, which cooked its books in 2001 to qualify for membership in the euro club. The government never curbed shortfalls in its budget when times were good, and expanded employment by adding to government rolls, even as an inefficient tax collection system reduced tax receipts. Now, Greece has admitted its budget deficit stands at nearly 13 percent of gross domestic product, while debt levels are well beyond what the rules of euro membership allow. Greece is now trying to manage its deficit with a partial freeze on civil servants' pay and a hike in the fuel tax. Greek customs and tax officials began a 48-hour walkout Thursday, choking the flow of imports, and there were threats of more strikes. 