Federal Reserve Vice Chairman Stanley Fischer on Monday warned of the dangers of low rates.
In prepared remarks for a speech at the Economic Club of New York, Fischer suggested that low rates can lead to longer and deeper recessions, making the economy more vulnerable.
He added they can also threaten financial stability, although the evidence so far doesn't show a heightened threat of instability.
Fischer said the central bank has a limited ability to combat recessions because it does not control all the factors leading to depressed rates.
Though Yellen said it's useful to consider the benefits of such an economy, Fischer did not specifically relate his remarks to a preference for monetary policy.
The policymaking Federal Open Market Committee hasn't approved an interest rate increase since December. However, pressure is building. Three FOMC members dissented at the September meeting, believing the committee should have raised it key funds rate a quarter-point.
The Fed's vice chair said technology and demographics are contributing to low rates, but are out of the Fed's control.
Fischer said other reasons contributing to weak growth include productivity and labor force growth, an aging population, weak investment and weak foreign growth.
Stocks continued to hold lower, following Fischer's comments.
--CNBC's Jeff Cox contributed to this report.