WASHINGTON (AP) — Federal Reserve Chairman Ben Bernanke warned Monday that it's too soon to know whether the economic recovery will last and again pledged to hold rates at record-low levels for an "extended period."

The Fed chief's speech to the Economic Club of Washington made clear he thinks the economy will struggle even as it recovers from the recession. He said the economy confronts "formidable headwinds" — including a weak job market, cautious consumers and tight credit.

Those forces "seem likely to keep the pace of expansion moderate," he said.

The central bank has leeway to keep rates low because inflation is under control and is expected to stay tame because of the economy's weakness.