WASHINGTON — Chairman Ben Bernanke said today the Federal Reserve's timetable for reducing its bond purchases is not on a “preset course” and the Fed could increase or decrease the amount based on how the economy performs.

Bernanke is telling lawmakers in prepared testimony that the job market has made some progress since the Fed began buying $85 billion a month in bonds in September. And he repeated his belief that the Fed could slow that pace later this year if the economy strengthens.

But Bernanke cautioned that the Fed wants to see substantial progress in the job market before scaling back the bond purchases. If conditions worsen, the Fed could maintain its current pace or even increase it. The bond purchases are intended to keep long-term interest rates low and encourage borrowing and spending.

Investors reacted positively to Bernanke's remarks. The yield on the benchmark 10-year Treasury note fell from 2.55 percent to 2.50 percent minutes after the text of his comments were released as investors bought government bonds. Dow index futures turned slightly higher.