IMF chief Christine Lagarde has called for countries to "act now and act together" to keep on the path to economic recovery. Ms Lagarde was speaking after another week of volatility on the world's share markets. In Europe, the main share indexes in London, Paris and Frankfurt all fell about 4% over the week. Meanwhile, British Chancellor George Osborne warned time was running out to tackle the eurozone debt crisis. Speaking in Washington, where the G20 is also gathering, Mr Osborne said European leaders had six weeks to end the crisis.