Federal Reserve Chairman Ben Bernanke said on Friday that high unemployment and low inflation point to a need for a further easing of the nation’s monetary policy, but he offered no details on the central bank’s next step.

"There would appear – all else being equal – to be a case for further action," Bernanke said at a conference sponsored by the Boston Federal Reserve Bank.

He said a prolonged period of high unemployment could pose a risk to the recovery’s sustainability and said the low level of inflation meant the risk of a dangerous downward slide in prices was greater than desirable.

However, he said policymakers were still weighing how aggressive they should be.

The U.S. dollar fell against the euro and yen on Bernanke’s remarks, and stock index futures turned positive. Prices for U.S. government debt rose, but only briefly.

Since the nation’s recovery began showing signs of fading over the summer, the Fed has steadily built up expectations that it would renew its large-scale asset buying to support growth.

Most economists expect around $500 billion in easing before the end of the year, a Reuters poll showed.

Bernanke said that while the central bank, which pushed overnight interest rates to zero in December 2008, has the tools to ease financial conditions further, it still needed to proceed cautiously.

"Nonconventional policies have costs and limitations that must be taken into account in judging whether and how aggressively they should be used," he said,

Even though the deep recession ended in June 2009, unemployment still hovers at a lofty 9.6 percent, and core inflation, as measured by the Fed’s favorite gauge, has slipped to 1.4 percent.

A report on Friday showed the more popular Consumer Price Index rose just 0.1 percent in September, while the core CPI, which strips out food and energy costs, was flat for a second straight month. Over the past year, the core CPI has risen just 0.8 percent.