European Central Bank President Jean-Claude Trichet, U.S. Federal Reserve Chairman Ben Bernanke, and Bank of Japan Governor Masaaki Shirakawa walk together outside the Jackson Lake Lodge.(REUTERS)

JACKSON HOLE, Wyo., Aug. 23 (Reuters) – US Federal Reserve Chairman Ben Bernanke and other central bankers said on Friday the worst global recession in 70 years was nearing a close but warned it would be a long, slow climb back to normal growth.

At an annual Fed retreat set against the backdrop of the Grand Teton mountains, the officials said the coming recovery would have its ups and downs, and it was too soon to withdraw trillions of dollars in government and central bank support.

''After contracting sharply over the past year, economic activity appears to be leveling out, both in the United States and abroad, and the prospects for a return to growth in the near term appear good,'' Bernanke said.

But both Bernanke and European Central Bank President Jean-Claude Trichet said there was still much work to be done to restore the global economy to self-sustaining growth.

Trichet said he was ''a bit uneasy'' about talk of a return to normal and that policy-makers ''should be as active as possible.''

In the past couple of weeks, reports have shown that some major economies, including Germany, France and Japan, generated positive growth in the second quarter, and polls showed that most economists think the current quarter will mark the end of the US recession, which started in December 2007.

John Lipsky, the No. 2 official at the International Monetary Fund, said the outlook had not shifted sharply and noted that growth was being fueled by stimulative policies.

Surprisingly strong US home sales figures, released just as Bernanke was beginning his speech, added to investor optimism that recovery was in sight, sending stock markets higher while US government debt prices fell.

The conference, held at a no-frills rustic lodge in a national park in the western state of Wyoming, is a big draw for the world's leading monetary policy-makers and economists.