* Bonds rise on safety buying
* Russia says Ukraine on brink of civil war
* Brent oil falls as investors weigh Libya, Ukraine (Adds close of European bond, stock markets)
By Herbert Lash
NEW YORK, April 15 (Reuters) - Global equity markets declined and government debt rose on Tuesday over rising tensions in Ukraine after Russia declared the country on the brink of civil war and as disappointing corporate results dogged U.S. and European stock markets.
The New York Federal Reserve said its Empire State general business conditions index fell to a five-month low of 1.29 in April from a reading of 5.61 the month before, pulled down by a plunge in new orders.
A separate report showed confidence among U.S. homebuilders remained downbeat as the NAHB/Wells Fargo Housing Market index rose only a point to 47 in April, the third month in a row it was below 50. Readings below 50 mean more builders view market conditions as poor than favorable.
Worries over escalating tension in Ukraine and weak results by bellwethers including Nestle held back stocks in Europe. Most of Wall Street traded flat but Nasdaq slumped on another round of selling in technology and biotech names.
The momentum stocks, those believed by investors to have high growth potential, have been under pressure after soaring prices took their valuations to unsustainable levels.
The Nasdaq Biotech index dropped 1.1 percent.
"They reached a level where the pricing was absurd in terms of the valuation of these companies, and for whatever reason, the market has woken up to the fact and is now correcting to get them back down to a reasonable valuation," said Stephen Massocca, managing director of Wedbush Equity Management LLC in San Francisco.
"And suddenly everyone realizes the emperor has no clothes."
Russia declared Ukraine on the brink of civil war as Kiev said an "anti-terrorist operation" against pro-Moscow separatists was under way, with troops and armored personnel carriers seen near a flashpoint eastern town.
"We're cautious in the short term, we're waiting to see how the geopolitical situation evolves. There are a lot of uncertainties about Ukraine, which could become a negative catalyst for stocks if things spin out of control," said Barclays France director Franklin Pichard.
MSCI's all-country world stock index fell 0.35 percent, while the FTSEurofirst 300 index of top European shares closed down 0.96 percent at 1,306.85.
The Dow Jones industrial average rose 6.96 points, or 0.04 percent, to 16,180.2. The S&P 500 gained 1.38 points, or 0.08 percent, to 1,831.99 and the Nasdaq Composite dropped 24.936 points, or 0.62 percent, to 3,997.759.
Corporate results also weighed on U.S. stocks. Of the 36 companies in the S&P 500 that have reported earnings to date for the first quarter, 52.8 percent have reported earnings above analyst expectations.
In a typical quarter over the past two decades, 62 percent of companies beat estimates.
U.S. Treasuries prices gained as the rising tensions in Ukraine sparked a safety bid for U.S. bonds. The weak New York state manufacturing survey and housing data pointed to sluggish economic momentum.
Benchmark 10-year notes were up 6/32 in price to yield 2.6175 percent.
The dollar pared gains against the euro after traders discounted comments from European Central Bank policy-makers and a slight uptick in U.S. inflation did not suggest a potential change in the Federal Reserve's dovish monetary stance.
The euro recovered against the dollar after ECB President Mario Draghi indicated on Saturday that the central bank would act to prevent deflation in the euro zone.
The impact of Draghi's comments receded somewhat, with traders awaiting more decisive action from the ECB.
The dollar edged up against the euro, trading up 0.05 percent against the dollar at $1.3812.
The dollar was down 0.06 percent against the Japanese yen at 101.76, and was up 0.01 percent against the Swiss franc to trade at 0.8797 francs.
The U.S. dollar index was last up 0.07 percent.
Brent crude fell further below $109 as investors weighed the prospect of a gradual recovery in Libyan oil exports against rising tension between Russia and Ukraine.
Brent shed 17 cents to $108.90 a barrel. U.S. oil dropped 20 cents to $103.85 a barrel.