US STOCKS-Futures dip amid uncertainty over Ukraine
* 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. Continuación...