* U.S. and EU impose sanctions on Russian officials
* Fed in view as two-day meeting set to begin
* Hertz rises in premarket, to spin off unit for $2.5 bln
* Futures down: Dow 18 pts, S&P 3.6 pts, Nasdaq 8.75 pts
By Ryan Vlastelica
NEW YORK, March 18 (Reuters) - U.S. stock index futures were flat on Tuesday, with investors reluctant to make big bets following a sharp rise in the previous session, amid continued uncertainty over Ukraine.
* Russian President Vladimir Putin said Russia would move forward with procedures to annex Ukraine's Crimean region, defying Western sanctions in the most serious crisis between Russia and the United States since the Cold War.
* Late Monday, the United States and the European Union imposed personal sanctions on a handful of officials from Russia and Ukraine who were accused of involvement in Moscow's military seizure of the Black Sea peninsula, most of whose 2 million residents are ethnic Russians.
* While few U.S. companies have heavy exposure to the region, investors are worried that tensions could increase, or that Russia may respond to the sanctions with actions of its own.
* Investors were also looking ahead to a two-day meeting of the U.S. Federal Reserve's policy-setting committee, which begins Tuesday. The central bank is not expected to deviate from previously announced policy plans, but as the Fed's stimulus has kept a floor under equity prices, market participants will be attuned to any hint of a change.
* S&P 500 futures fell 3.6 points and were below fair value, a formula that evaluates pricing by taking into account interest rates, dividends and time to expiration on the contract. Dow Jones industrial average futures fell 18 points and Nasdaq 100 futures fell 8.75 points.
* February consumer price and housing starts data are scheduled for release at 8:30 a.m. ET (1230 GMT). Prices are seen rising 0.1 percent while housing starts are expected to rise modestly from the previous month.
* In company news, Hertz Global Holdings Inc said it would spin off its equipment rental business for $2.5 billion, and that part of the proceeds would be used to fund a stock buyback program.
* American Express Co said late Monday four financial investors had committed a total of $900 million to a business travel joint venture, the largest single investment ever made in a travel management company.
* Major U.S. indexes rose about 1 percent on Monday as tensions with Ukraine appeared to ease. The rally continued a recent trend of investors using market pullbacks as buying opportunities following a 2 percent decline in the S&P 500 last week. Key indexes have not had a sustained drop in more than a year.