Wall Street ended lower yesterday as investors fretted over renewed uncertainties about the Federal Reserve's plan to raise interest rates this year. Also weighing on stocks, the International Monetary Fund's Managing Director, Christine Lagarde warned of increasing risks to global economic growth, unless there were stronger measures by policymakers. Lagarde's comments come a week after Fed Chair Janet Yellen urged caution on rate hikes, citing a shaky global economy and low oil prices. However, some Fed officials called for an aggressive monetary policy, sparking concerns about the timing and the number of rate hikes this year. While the Fed has projected two hikes in 2016, traders are pricing in only one, with an even chance that the central bank may pull the trigger in June. So the Dow Jones Industrial Average fell 134 points, or 0.8 percent, to close at 17,603. The Standard & Poor's 500 index lost 21 points, or 1 percent, to 2,045. And the Nasdaq Composite index shed 48 points, or 1 percent, to 4,844.