TREASURIES-Bonds fall as Moody's puts US on downgrade review

* Moody's places U.S.'s Aaa rating on review for downgrade

* Fed's Bernanke hints is open to stimulus to help economy

* Solid $21 bln 10-year note sale soothes supply worries

* Fitch downgrades Greece further into junk territory
(Updates market action, adds new quotes, byline)

By Richard Leong

NEW YORK, July 13 (Reuters) - U.S. Treasuries prices fell
late on Wednesday after Moody's Investors Service put the
United States' coveted Aaa-rating on review for a possible
downgrade, reducing the appeal of the upcoming 30-year bond
supply.

The ratings agency cited the growing risk that Washington
will not raise its $14.3 trillion debt ceiling "on a timely
basis." The failure to increase its borrowing limit will result
in a U.S. default, which investors and experts say could wreak
havoc across financial markets. For details, see
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"It will make it a little tougher to sell," Carl Kaufman,
portfolio manager at Osterweis Capital Management in San
Francisco, said of the upcoming $30 billion 30-year bond sale.

As the European debt crisis continues to fester, however,
"people still look at Treasuries as the safest haven in the
world," Kaufman said.

The news from Moody's took the wind out of a late market
bounce spurred by a solid 10-year note auction and lingering
fears over the euro zone debt crisis. These factors countered
earlier profit-taking, which snapped a three-day advance.

U.S. benchmark 10-year Treasury notes US10YT=RR last
traded down 2/32 in price with a yield of 2.88 percent, up 1
basis point from late on Tuesday, according to Tradeweb.

Federal Reserve Chairman Ben Bernanke had earlier signaled
before Congress that he would be ready to inject more stimulus
if the U.S. economy and inflation slow much more.
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"Bernanke was quite dovish," said Larry Dyer, head of U.S.
rates strategy in HSBC Securities USA in New York. "The economy
is stuck in a ditch. It's not getting out of the ditch anytime
soon."

The Treasuries market was considered overstretched and was
poised for a pullback after benchmark notes booked their
strongest three-day advance since May 2010.

The pullback was briefly tempered after a successful
10-year note sale following Tuesday's solid three-year sale.

"The market has regained some confidence with these two
auctions," said Charles Comiskey, head of Treasury trading at
Bank of Nova Scotia in New York.

The U.S. Treasury Department will complete this week's $66
billion in coupon-bearing supply on Thursday with a $13 billion
reopening of a 30-year bond issue originally sold in May.

Fitch's downgrade of Greece deeper into junk territory
rekindled anxiety that Europe's fiscal woes could spiral into a
a global crisis, causing some traders to close out earlier bets
against Treasuries before the Moody's review of United States'
credit ratings.

"People don't want to go that short by the end of day given
the uncertainty in Europe," Comiskey said.