(Bloomberg News) The Federal Reserve pledged for the first time to keep its benchmark interest rate at a record low at least through mid-2013 in a bid to revive the flagging recovery after a worldwide stock rout.

The Federal Open Market Committee discussed a range of policy tools to bolster the economy and said it is "prepared to employ these tools as appropriate," it said in a statement today in Washington. Three members of the FOMC dissented, preferring to maintain the pledge to keep rates low for an "extended period."

The decision represents the biggest effort since November to spark the U.S. economy and revive confidence while stopping short of initiating a third round of large-scale asset purchases. Chairman Ben S. Bernanke and his colleagues acted after reports showed the economy was slowing and an unprecedented downgrade to the U.S. credit rating sent stocks tumbling from Sydney to New York.

The Fed offered a dimmer view of the economy than it did in the last statement in late June. "Economic growth so far this year has been considerably slower than the committee had expected," it said. The Fed also said it expects a "somewhat slower pace of recovery over coming quarters," adding that "downside risks to the economic outlook have increased."

Stocks pared gains and Treasuries declined after the statement. The Standard & Poor's 500 Index rose 0.6 percent to 1,126.21 at 2:25 p.m. in New York after advancing as much as 2.9 percent.

Target Rate

The Fed left its target for the federal funds rate in a range of zero to 0.25 percent, where it's been since December 2008. It said it will maintain its policy of reinvesting maturing securities without saying for how long.

The vote was 7-3. Richard Fisher, president of the Dallas Fed, Charles Plosser of Philadelphia and Narayana Kocherlakota of the Minneapolis Fed all dissented. It was the first time under Bernanke that three FOMC members dissented.

The Fed's decision came after Standard & Poor's unprecedented downgrade of the U.S. credit rating on Aug. 5 sent share prices tumbling on concern a global economic slowdown will deepen. Fitch Ratings and Moody's Investors Service affirmed their top grades for U.S. debt.

The Standard & Poor's 500 Index tumbled 6.7 percent yesterday in New York, its biggest decline since December 2008. The drop has wiped out all the gains in stocks since Nov. 3, 2010, when the Fed announced it would buy $600 billion of government bonds, its second round of asset purchases.

Treasuries surged yesterday as investors sought the safety of government debt. Yields on 10-year notes fell 22 basis points, or 0.22 percentage point, to 2.32 percent, the least since January 2009.