TREASURIES-US gov bond prices soar as Fed sparks economy fear

* Treasuries prices leap, yields plunge on economy fears

* 2-, 3-, 5-year note yields fall to record lows

* 10-year note yields test record 2008 low

* Investors seek stimulus at Bernanke Jackson Hole speech (Adds details, updates prices)

By Karen Brettell

NEW YORK, Aug 9 (Reuters) - Short-dated US Treasury yields fell to record lows on Tuesday after the Fed said it would keep rates near zero for two years, causing speculation the central bank would return to the bond market to stimulate the economy.

A little more than a month after the Fed ended its last major Treasury puchase program, analysts said the rapidly deteriorating economy could lead the Fed to signal another initiative later this month.

Much of the speculation is centered on Chairman Ben Bernanke's scheduled appearance at the Jackson Hole conference on Aug. 26, where last year his comments were interpreted as signalling the quantitative easing program that just ended.

"It leaves us all eagerly awaiting Bernanke's Jackson Hole speech," said Carl Lantz, interest rate strategist at Credit Suisse in New York.

"One suspects that he'll have to float yet another program, whether it's extending duration or just buying more Treasuries like a QE3," he said.

Yields on shorter-dated debt plunged, with two-year, three-year and five-year notes all setting new lows.

"We keep going through yields we haven't been through," said James Newman, head of Treasury and Agency trading at Keefe, Bruyette and Woods in New York.

Benchmark ten-year notes also tested their record low of 2.04 percent, initially set in December 2008, before rising back to around 2.21 percent.

The statement overturned earlier weakness, when investors had ventured back into riskier assets, looking for value after Monday's global selloff in stocks, corporate bonds and industrial commodities.

Two-year notes US2YT=RR were last up 4/32 in price to yield 0.20 percent, and three-year notes US3YT=RR rose 10/32 in price, with yields dropping to 0.32 percent.

Five-year notes US5YT=RR rose 12/32 in price, with yields falling to 1.00 percent while ten-year notes US10YT=RR were last up 10/32 in price to yield 2.28 percent.

(Additional reporting by Richard Leong and Ellen Freilich; Editing by Chizu Nomiyama)