WASHINGTON, Feb. 25 (AFP) – Federal Reserve chairman Ben Bernanke signaled that the US central bank was not yet ready to abandon its ultra-low interest rates as it tried to keep a tentative economic recovery on track.

The Fed chairman, in his semiannual report to Congress on Wednesday, said he saw unemployment remaining stubbornly high, which would require the Fed to stay on a stimulative path, doing little to change monetary policy.

The report came after last week's surprise increase in the discount rate for emergency bank loans prompted speculation that the Fed might be moving faster than anticipated to a tighter monetary stand.

In the House of Representatives Financial Services Committee, Bernanke said the economy had begun to show growth in the second half of 2009 after a massive stimulus effort from the Fed and the US government.

But he said the recovery ''probably will be tempered by households' desire to rebuild wealth, still-tight credit conditions facing some borrowers, and, despite some tentative signs of stabilization, continued weakness in labor markets."