U.S. stocks opened flat on Friday as investors looked ahead to a speech by Federal Reserve Chair Janet Yellen and digested the latest flare of tensions between Ukraine and Russia.

The Dow Jones industrial average .DJI fell 6.42 points or 0.04 percent, to 17,033.07, the S&P 500 .SPX lost 0.84 points or 0.04 percent, to 1,991.53 and the Nasdaq Composite .IXICadded 2.32 points or 0.05 percent, to 4,534.43.

(Reporting by Ryan Vlastelica; Editing by Bernadette Baum)