Dallas Fed President Richard Fisher, a top U.S. Federal Reserve official repeated on Thursday that the Federal Reserve's interest rates would remain at low levels until 2015.

"We expect rates to stay at these low levels until 2015," Fisher said, adding that the Fed had done more to provide certainty by for example repeating such forecasts than the government had done during the crisis.

"We provide more certainty than the fiscal authorities," he added.

The Fed has said it expects to hold rates near zero until at least mid-2015, but several officials have suggested replacing this calendar commitment with a set of economic variables, or thresholds, that would signal when the time to raise rates was drawing near.

Fed Chairman Ben Bernanke said last week that adopting numerical thresholds for unemployment and inflation could be a "very promising" step to develop the Fed's communication strategy, but stressed that it was still under discussion.

Fisher opposes such suggestions and said earlier this month that it would be a "bad idea" to tie monetary policy to specific economic conditions.