* Brent jumps over 2 pct on Libya, lack of OPEC action
* Portugal sells bonds, long-term financing worries remain
* European stocks close down, IBM shares support Dow
(Updates Treasuries prices rising further after auction)
By Walter Brandimarte
NEW YORK, March 9 (Reuters) - Brent oil prices jumped on Wednesday, weighing on global stocks, as escalating violence in Libya increased fears higher energy costs could choke the global economic recovery.
U.S. Treasuries prices were boosted by a safety bid following the sale of Portuguese debt at unsustainably high yields. Demand for safe-haven assets also translated into strong demand in an auction of 10-year Treasuries.
Mining stocks led European equity markets lower as prices of key base metals fell on worries demand for raw materials could be hit if economic growth slowed.
On Wall Street, however, the Dow Jones clawed back into positive territory with a jump in IBM shares. The tech giant's stock reached an all-time high one day after it promised to nearly double its profit by 2015. For details, see [
]Brent oil <LCOc1> jumped more than 2 percent to $115.65 a barrel as fighting in Libya intensified and OPEC saw no need for an emergency meeting to consider raising oil output. Worries that the unrest could spread into the Middle East also left investors jittery.
"It's a fear trade," said Michael Hewson, an analyst at CMC Markets. "It's about the fear of these troubles escalating -- there is some concern about how the Saudi Day of Rage will go on Friday."
Activists in Saudi Arabia have set up Facebook pages calling for protests on March 11 and 20.
Expectations the Organization of the Petroleum Exporting Countries would respond to the decline in Libya's output by rising production had driven oil prices lower on Tuesday, one day after they hit a 2-1/2-year high.
In New York, however, U.S. crude oil futures <CLc1> seesawed between gains and losses as investors eyed both the violence in Libya and a greater-than-expected rise in U.S. stockpiles last week. Oil in New York was little changed at $104.95 a barrel.
World stocks fell, with the MSCI All-Country World Index <.MIWD00000PUS> down 0.11 percent at 343.22 points.
European equities fell on fears rising oil prices could hurt the economy and fan inflation. The FTSEurofirst 300 <
> index of top European shares closed down 0.23 percent at 1,144.75 points, after rising to a high of 1,153.62 during the session.On Wall Street, the Dow Jones inched higher as IBM <IBM.N> shares soared 2.7 percent, to $166.65. A number of analysts raised their target price for the tech giant's stock after the company reaffirmed its profit target. [
]The Dow Jones industrial average <
> was little changed at 12,214.68, while the Standard & Poor's 500 Index <.SPX> was down 2.63 points, or 0.2 percent, at 1,319.19. The Nasdaq Composite Index < > fell 17.75 points, or 0.64 percent, to 2,748.02.PORTUGAL IN NEED
Prices of U.S. government bonds rose as investors moved to safe-haven assets after an auction of Portuguese debt reminded them of the financial troubles of peripheral euro zone countries.
U.S. benchmark 10-year Treasury notes <US10YT=RR> rose 21/32 in price, with the yield at 3.4675 percent. Prices rose further after the high yield in an auction of $21 billion of reopened 10-year notes came in below market expectations.
Portugal was able to sell 1 billion euros in two-year bonds at an auction but its borrowing cost was the highest since it joined the euro. Lisbon said such yields were unsustainable in the long run without Europe-wide action.
"The auction was always going to go OK ... but I don't think clients are particularly interested in buying the bond," said a trader in London. "The problems remain -- we've got the March 25 summit coming up, we've got continued selling in Greece."
Euro zone leaders meet ahead of the summit on Friday. The bloc's 17 heads of state are expected to agree the next cautious steps in their year-long effort to quell the region's debt crisis but the meeting is unlikely to produce a breakthrough. [
]The euro fell from an earlier high and traded practically flat against the dollar as expectations of a euro-zone interest rate hike next month faded somewhat.
Investors worry that monetary policy tightening by the European Central Bank would raise borrowing costs even higher for peripheral euro zone economies.
The European single currency <EUR=> was practically unchanged at $1.3906, falling from an earlier four-month high of $1.4036 on electronic trading platform EBS.
Copper for three-months delivery <CMCU3> on the London Metal Exchange closed at $9,275 a tonne, down from a close of $9,530 a tonne on Tuesday. (Additional reporting by Kirsten Donovan, Karen Brettell, Edward Krudy, Claire Milhench; Editing by Andrew Hay)