Federal Reserve policy makers will replace some bonds in their portfolio with longer-term Treasuries in an effort to further reduce borrowing costs and keep the economy from relapsing into a recession.

The central bank will buy $400 billion of bonds with maturities of six to 30 years through June while selling an equal amount of debt maturing in three years or less, the Federal Open Market Committee said today in Washington after a two-day meeting.

The action is intended to “put downward pressure on longer-term interest rates and help make broader financial conditions more accommodative,” the FOMC said in a statement. The Fed will also reinvest maturing mortgage debt into mortgage-backed securities instead of Treasuries. Three officials dissented, the same as at the prior meeting in August.