U.S. economy risks new downturn: economist Feldstein

JACKSON HOLE, Wyoming (Reuters) - The U.S. economy has improved but there is still a risk of another slowdown, prominent economist Martin Feldstein said on Saturday.

"We are going to see a good third quarter ... but I wonder if it is really sustainable or whether we could have another slowdown or indeed downturn after the third or fourth quarter," Feldstein, a professor at Harvard and formerly head of the National Bureau of Economic Research, told Reuters Television.

In an interview on the sidelines of the Federal Reserve's annual Jackson Hole conference, Feldstein said he did not expect the Fed to withdraw its extraordinary monetary stimulus and raise interest rates "any time soon".

"I think they will wait to see how the economy is going," said Feldstein, who is still a member of the NBER panel that dates recessions.

He said he would not read too much into a recent tick up in U.S. existing home sales as they also reflected a rise in foreclosure sales.

"We have to see another month or two before I am convinced that house prices have really bottomed out," he said.

Asked about the chances for President Barack Obama to reappoint Ben Bernanke, whose term as chairman of the Fed -- the U.S. central bank -- expires at the end of January, he said:

"I think it would be a good reappointment, I think he has been remarkably creative and technically good. But it's up to the president."

(Reporting by Kristina Cooke and Dan Burns; Editing by James Dalgleish)