WASHINGTON (AP) _ U.S. helicopters have begun attacking Saddam Hussein's Republican Guard forces arrayed around Baghdad, a Pentagon official said Monday.

Asked about ground forces, Maj. Gen. Stanley McChrystal said, ``We have not gotten into direct firefights with Republican Guard forces.'' The Army's Third Infantry division moved to within 50 miles of the Iraqi capital.

He said that thus far in the war, 2,000 precision-guided weapons have been used against the Iraqis.

``All of the pieces are falling into place,'' McChrystal told a Pentagon briefing.