* Yen builds on sharp overnight gains against dollar, euro
* Russian shares plummet before Sunday's Crimea referendum
* World stock index falls but U.S. stocks little changed
By Caroline Valetkevitch
NEW YORK, March 14 (Reuters) - Growing tension between the West and Russia ahead of Ukraine's weekend referendum in Crimea pushed down stocks on major world markets on Friday and drove up buying of safe-haven gold and the yen.
Financial markets watched nervously as the West increasingly talked about sanctions and Russia hit back with promises of retaliatory measures and displays of military prowess. The vote being held on Sunday by pro-Moscow authorities is to determine if Crimea will join Russia.
Jitters also remained over the degree to which China's economy is slowing after unsettling data this week.
The MSCI global market index was down 0.5 percent and was on track for a loss of about 2 percent for the week, while gold prices reached their highest level in six months. Spot gold rose as much as 1.4 percent to its highest level since Sept. 9, and was last up 1 percent at $1,384.20 an ounce.
Moscow's MICEX index fell more than 5 percent before clawing back some of its losses to end down 0.9 percent. The rouble was steady but close to recent record lows.
Russia's central bank on Friday kept lending rates on hold after raising them two weeks ago and said it would fight for financial stability after the standoff with the West over Crimea. The bank said there would be no easing of rates in the months ahead, suggesting it expects more tough times ahead for the rouble and for stocks, which have lost about a quarter of their value since mid-February.
Part of the concern over the Crimea referendum on Sunday is that it could encourage other pro-Moscow parts of the country to follow suit and potentially embolden Russia in the region.
"There is a lot of anticipation about that Crimea vote coming up, so that is out there, a little bit of uncertainty," said Ryan Detrick, senior technical strategist at Schaeffer's Investment Research.
U.S. Secretary of State John Kerry met Russian counterpart Sergei Lavrov in London in last-ditch diplomatic efforts to defuse tensions, but Moscow and the West appeared increasingly far apart.
Russia shipped more troops into Crimea on Friday and repeated its threat to invade other parts of Ukraine. A German newspaper reported that the chief executive officers of Russia's two largest firms are on a list of those who may be hit next week with European and U.S. sanctions.
U.S. stocks were little changed and all three major indexes were on track for a weekly decline. The Dow Jones industrial average rose 1.38 points or 0.01 percent, to 16,110.27, the S&P 500 gained 0.24 points or 0.01 percent, to 1,846.58 and the Nasdaq Composite dropped 1.609 points or 0.04 percent, to 4,258.811.
The FTSEurofirst 300 index of top European shares closed down 0.7 percent. Shares of companies most exposed to Russia fell, including Danish brewer Carlsberg, down 0.5 percent.
Latin American stocks also fell, with Mexico's IPC stock index down 0.4 percent.
In the foreign exchange market, the latest developments in the Ukraine crisis sent the safe-haven yen soaring against both the dollar and the euro. The yen was headed for its biggest weekly gain in more than a month against the dollar.
The euro fell as much as 0.5 percent against the yen in early U.S. trading before trimming losses to trade 0.25 percent lower at 140.88 yen.
The dollar fell 0.5 percent to 101.36 yen. On the week, the dollar has lost 1.7 percent, on track for its biggest loss since late January.
"I don't think anyone wants to hold any large risky positions going into the weekend," said Shaun Osborne, chief foreign exchange strategist at TD Securities in Toronto.
U.S. Treasuries prices inched up on the Ukraine worries and after data showed a dip in U.S. consumer sentiment. The 10-year U.S. Treasury note was last up 1/32 in price to yield 2.648 percent, compared with a yield late Thursday of 2.653 percent.
U.S. economic data showed consumer sentiment weakened in early March as an unusually harsh winter appeared to dim views on the economy's prospects.
Foreign central banks' overall holdings of U.S. marketable securities at the Federal Reserve plunged in the latest week, data from the U.S. central bank showed.
The Fed said its holdings of U.S. securities kept for overseas central banks sank by $106.142 billion in the week ended March 12, to stand at $3.206 trillion. The tumble brings the total on deposit with the Fed to the lowest level since December 2012.
In the oil market, Brent crude was up 87 cents at $108.26 a barrel, while U.S. crude futures rose 67 cents to settle at $98.87.
With Russian assets continuing to slump, investors were taking the view that while the situation did not look good, Vladimir Putin and the Kremlin were unlikely to flinch.
"Obviously, Russia will not back down, so it all points to an escalation," Viktor Szabo, a fund manager at Aberdeen Asset Management who holds Ukrainian and Russian bonds, said.
Copper, whose demand is seen falling as Chinese economic growth slows, edged higher but was down sharply for the week.
Benchmark three-month copper on the London Metal Exchange, untraded at the close, was bid at $6,468.50, up 0.8 percent from Thursday's close. It sank to a 44-month low of $6,376.25 on Wednesday.
"We have very bad headline risks now, including Ukraine, Russia, Venezuela, growth fears in China and elections in many large emerging economies," said Jorge Mariscal, chief investment officer of emerging markets at UBS Wealth Management.