AFP, Washington : The International Monetary Fund Friday warned emerging economies to shore up their defenses amid challenging global turmoil that has sparked a broad-based sell-off in financial markets. An IMF spokesperson said they could not find a single trigger for the turmoil, but also appeared to warn central banks generally to be cautious about tightening monetary conditions. “Many emerging economies, along with other asset classes, have come under renewed market pressure in recent days,” the spokesperson said in an emailed statement. “While it is difficult to pinpoint a single trigger for the sell-off, the turbulence underscores the challenging situation that many countries face as a result of tighter external financing conditions, slower growth, and softer commodity prices.” The IMF noted that several countries had responded “forcefully”, not mentioning any by name but apparently referring to sharp interest rate hikes by the central banks of South Africa and Turkey, aimed at stabilizing their sinking currencies and stemming capital flight. However, the spokesman said, ‘the turbulence highlights the need for coherent macroeconomic and financial policies, good communication, and, in some cases, the need for urgent policy action to improve fundamentals and policy credibility.” Moreover, the spokesperson added, “The turbulence also underscores the need for vigilance among central banks over liquidity conditions in international capital markets.” Many officials in emerging market economies have pointed a finger at the US Federal Reserve’s cuts to its stimulus program for sending US dollar interest rates high and provoking a strong, sustained outflow from stocks and currencies in those countries. Speaking on Bloomberg TV, on Thursday India’s central bank chief Raghuram Rajan assailed the Fed and central banks at other leading economies for not weighing the impact of monetary tightening on developing economies.