U.S. stocks fell at the open on Friday as market uncertainty over Egypt grew amid risks of spreading unrest in the Middle East.

Protesters insisted Egyptian President Hosni Mubarak step down. The increasingly tense situation raised fears of violence in the most populous Arab nation, a key U.S. ally in an oil-producing region.

The Dow Jones industrial average <.DJI> was down 34.51 points, or 0.28 percent, at 12,194.78. The Standard & Poor's 500 Index <.SPX> was down 4.49 points, or 0.34 percent, at 1,317.38. The Nasdaq Composite Index <.IXIC> was down 7.04 points, or 0.25 percent, at 2,783.41.

Domestically, the Obama administration declared the public-private housing finance model in place for the past four decades was dead but pledged to continue backing existing obligations of Fannie Mae and Freddie Mac .

(Reporting by Angela Moon, Editing by Kenneth Barry)