U.S. stocks extended gains on Wednesday, with the S&P and the Nasdaq near session highs after the Federal Reserve signaled it was willing to maintain its extensive support for the U.S. economy and corporate earnings continued to impress.

The Fed's policy-setting Federal Open Market Committee said in a statement it intends to complete its $600 billion bond buying program in June as scheduled.

The tweaks in the QE2 language strongly suggest they are going to continue not only with QE2 but reinvesting mortgage cash flows, said Max Bublitz, chief investment strategist at SCM Advisors in San Francisco.

I don't think anybody thinks this is going to be the highlight of the day, Bublitz said of the FOMC's statement. It is the press conference.

Market gains were limited, however, as investors dissected comments from Fed Chairman Ben Bernanke, who is holding his first-ever press conference.

General Electric led the Dow higher, rising 3.1 percent to $20.73 after the company's finance chief said the company's profit growth over the next few years will be the fastest it had seen in a decade.

Boeing Co , Whirlpool Corp and WellPoint Inc also moved higher after topping analyst consensus expectations. Boeing, a Dow component, rose 0.8 percent to $76.17.

Whirlpool gained 0.3 percent to $88.14 and WellPoint added nearly 3 percent to $75.12.

According to Thomson Reuters data through Wednesday, of the 220 companies in the S&P 500 that have reported earnings, 73 percent have posted earnings above estimates.

The run of solid earnings has lifted the S&P 500 to levels not seen in nearly three years, with the index breaking through a key resistance level of 1,344 on Tuesday.

The Dow Jones industrial average <.DJI> gained 56.76 points, or 0.45 percent, to 12,652.13. The Standard & Poor's 500 Index <.SPX> gained 2.68 points, or 0.20 percent, to 1,349.92, close to its session high at 1,350.88. The Nasdaq Composite Index <.IXIC> gained 8.08 points, or 0.28 percent, to 2,855.62, just a touch off its session high.

Earlier, the Dow climbed as high intraday as 12,655.31.

(Reporting by Chuck Mikolajczak; Editing by Jan Paschal)