World shares fell and the euro came under renewed pressure on Thursday in what is shaping up to be a major flight to safety by investors fearful that the Greek debt crisis is gaining momentum, according to Reuters. Emerging markets, many of which are in reasonable economic shape and relatively removed from euro zone stress, were particularly hard hit, with shares down 1.4 percent. MSCI's all-country world stock index was down 0.6 percent. Europe's FTSEurofirst 300 index fell in early trading but then put in modest gains after strong results from BNP Paribas. It was up 0.3 percent. Japan's Nikkei tumbled more than 3 percent, catching up with other bourses after a three-day holiday. "There's no let-up in concerns that the euro zone debt crisis could continue to worsen and as a result equity markets across the globe remain under pressure," said Ben Potter, analyst at IG Markets. "The bull market always had to end somewhere and it looks like this could be the trigger." Focus was on a meeting of the European Central Bank, which is expected to leave interest rates unchanged but will almost certainly have to address the crisis, which saw deadly riots in Athens on Wednesday and pressure building on Spain, Portugal and others. "The ECB president will have to justify his recent decision to accept Greek bonds indefinitely as collateral regardless of their credit rating," Brown Brothers Harriman said in a note. "This has also raised speculation that the ECB may start outright purchases of euro zone government bonds," it said, adding that this was unlikely. EURO WOE The euro tumbled to a 14-month low against the dollar before recovering slightly on what traders said was Asian buying. European policymakers have warned the euro's survival depends on a life-support package for Greece agreed last weekend. This has ratcheted up risk aversion and boosted safe-haven demand for the dollar, pushing it to a one-year high versus a currency basket. "The driver remains concerns about the European situation, coupled with poor risk sentiment," said Kasper Kirkegaard, currency strategist at Danske in Copenhagen. The euro fell as low as $1.2737 according to electronic trading platform EBS, its weakest since March 2009. It was later flat at $1.2803. The common currency plumbed a one-year low against the yen of 118.85 yen on EBS, but recovered a bit to 120 yen. Euro zone government bond yields were mixed with the focus on the ECB meeting.