* Gold retreats as investors sell after safe-haven rally
* Tensions flare in North Africa as Libya fights protests
* U.S. stocks down 2 pct but Treasury bonds, oil rally
* Coming up: U.S. existing home sales data due Wednesday
(Recasts, adds comments, updates prices, new byline, dateline, previously LONDON)
By Frank Tang
NEW YORK, Feb 22 (Reuters) - Gold fell back toward $1,400 an ounce on Tuesday, breaking a six-session rally, as bullion investors took profits and as sharp losses in equities and other commodities markets prompted margin selling.
Bullion declined as world stocks fell sharply as revolt in Libya lifted crude prices to 30-month highs and rekindled fears of inflation and slower global growth if the unrest lingers. Agricultural commodities led by grains also fell broadly.
Investors also swapped riskier assets for safe-haven U.S. Treasury bonds, whose prices rose on Tuesday. Gold has been used as a speculative play as traders are betting rising political tensions across the Arab world will benefit gold.
"Libya is a political situation but it's not necessarily one that's going to spill over. Until there are additional signs of it spreading beyond Libya to other areas, gold is going to take a breather here," Frank McGhee, head precious metals trader of Integrated Brokerage Services.
Bullion gained 1.3 percent on Monday, hitting a seven-week high as as violence flared in north Africa and the Middle East, raising interest in the precious metal as a haven from risk.
Spot gold <XAU=> slipped 0.4 percent to $1,399.85 an ounce by 2:06 p.m. EST (1906 GMT), having earlier fallen as low as $1,392.54.
U.S. gold futures for April delivery <GCJ1> settled at $1,401.10, up $12.50 from Friday's close. Gold futures' gains were largely due to pent-up demand as U.S. markets were shut on Monday for the President's Day holiday.
Silver <XAG=> came under pressure in line with other industrial commodities, falling by as much as 4.3 percent to a low of $32.39 an ounce, as investors closed positions following a three-day rally that lifted prices by nearly 4 percent.
Silver lost 2.3 percent to $33.09, having earlier hit its highest since early 1980 at $34.30 an ounce, driven by limited supplies for near-term delivery and the prospect for rising demand as the wider economy recovers.
The gold-silver ratio, which shows how many ounces of silver can buy one ounce of gold, rose to around 42 from Monday's 13-year low near 41.
Spreading unrest in the Middle East had fueled six straight days of rising gold prices through Monday. A surge in the dollar earlier in the day pulled prices back from seven-week highs, but they have since recovered much of their early losses.
Libya's Muammar Gaddafi vowed to die in Libya as a martyr in an angry television address, as rebel troops said eastern regions had broken free from his rule in a burgeoning revolt. ID:nL3E7DM0K1]
"Bullion prices continue to draw support from ongoing unrest in the Middle East/North Africa region, also (from) a small dollar pullback this afternoon," said Andrey Kryuchenkov, an analyst at VTB Capital.
"Safe-haven buying remains the key driver behind the recent rally as players seek to offset currency and sovereign risk," he added.
ALL-TIME HIGH EYED
Gold is now just 2 percent below December's record high of $1,430.95 an ounce as economic uncertainty and lingering concerns about sovereign debt provided underlying support.
"Geopolitical tensions in the MENA region continue to fester, keeping risk aversion elevated (as evident in the poor performance of equities across the globe) and enhancing the appeal of safe-haven assets," Standard Bank said in a note.
"In addition, the surge in oil prices is keeping fears of rising global inflation alive."
Platinum group metals also fell sharply. Palladium <XPD=> dropped 6 percent to $802.97 for its biggest one-day loss since May, while platinum <XPT=> lost 3.3 percent to $1,786.50. Prices at 2:28 p.m. EST (1928 GMT)
LAST/ NET PCT YTD
CLOSE CHG CHG CHG US gold <GCJ1> 1401.10 12.50 0.9% -1.4% US silver <SIH1> 32.862 0.566 0.0% 6.2% US platinum <PLJ1> 1786.30 -57.00 -3.1% 0.5% US palladium <PAH1> 805.70 -52.00 -6.1% 0.3% Gold <XAU=> 1400.30 -5.65 -0.4% -1.3% Silver <XAG=> 33.11 -0.74 -2.2% 7.3% Platinum <XPT=> 1785.24 -61.21 -3.3% 1.0% Palladium <XPD=> 803.00 -50.88 -6.0% 0.4% Gold Fix <XAUFIX=> 1401.00 6.50 0.5% -0.7% Silver Fix <XAGFIX=> 32.89 -54.00 -1.6% 7.4% Platinum Fix <XPTFIX=> 1821.00 2.00 0.1% 5.2% Palladium Fix <XPDFIX=> 836.00 1.00 0.1% 5.7% (Additional reporting by Jan Harvey and Amanda Cooper in London; Editing by Marguerita Choy)