Yellen spells out Fed's taper policy
12 February 2014 Last updated at 02:02 GMT
In her first congressional testimony since taking over at the Federal Reserve, Janet Yellen said the central bank plans to continue scaling down its stimulus program.
However, she stressed that any reduction in its bond-buying program is contingent on an improvement in the US economy.
Stock markets around the world rose after her statement, which come after a rocky start to the year saw a sharp sell-off in emerging market currencies.
Samira Hussain has more from New York.