Top officials of the U.S. central bank say they will keep the key interest rate in its current ultra-low range until at least the middle of 2013.

That rate was cut to between zero and one-quarter of a percent in December of 2008.

Tuesday's Federal Reserve announcement is intended to bolster the faltering U.S. economy, which has been growing very slowly in the first half of 2011. Officials hope low interest rates lead to more borrowing and spending to stimulate the economy.

The Federal Reserve said it was concerned that economic growth had been slower than expected, and the U.S. labor market was weaker than anticipated.

The Fed meeting followed several days of losses in stock markets around the world and Friday's downgrade of U.S. credit by the Standard & Poor's rating agency.

Fed officials said they discussed other policy options to boost the economy.

U.S. President Barack Obama has called Treasury Secretary Tim Geithner to a meeting at the White House later Tuesday.