Stocks briefly added to gains on Wednesday after the Federal Reserve said economic activity remained at a low level as the year began but was improving modestly and more broadly.

The Dow Jones industrial average <.DJI> rose 39.75 points, or 0.37 percent, to 10,667.01. The Standard & Poor's 500 Index <.SPX> gained 6.76 points, or 0.59 percent, to 1,142.98. The Nasdaq Composite Index <.IXIC> was up 18.54 points, or 0.81 percent, at 2,300.85.

(Reporting by Leah Schnurr; Editing by Kenneth Barry)